Comprehensive and Detailed Explanation From Exact Extract:

To determine the correct definition of the Apex method for a Next Best Action strategy’s Enhance Element, we need to evaluate the syntax and requirements for an @InvocableMethod used in this context, focusing on its accessibility, input/output types, and compatibility with Next Best Action. Let’s analyze the problem and each option systematically, referencing Salesforce’s official documentation.

Understanding Next Best Action and Enhance Elements:

Next Best Action (NBA): NBA is a Salesforce feature that provides personalized recommendations to users, often used in process automation (e.g., via Flow or Einstein Next Best Action). It evaluates strategies to suggest actions, such as offering a discount to a Contact.

Enhance Element: In NBA, an Enhance Element allows developers to invoke custom logic (e.g., an Apex method) to modify or generate recommendations. The Salesforce Next Best Action documentation states: “An Enhance Element in a Next Best Action strategy can invoke an Apex method to dynamically generate or modify recommendations” (Salesforce Help, Next Best Action).

Apex Method Requirements:

The method must be annotated with @InvocableMethod to be callable from NBA or Flow.

It must be global and static to be accessible outside the class.

For NBA, the method typically returns recommendations as a List or List> (for bulk processing).

The input can be a List of a custom wrapper class (e.g., ContactWrapper) to pass data like Contact details.

The Apex Developer Guide specifies: “An @InvocableMethod must be global, static, and can take a List of inputs and return a List of outputs” (Salesforce Apex Developer Guide, InvocableMethod Annotation).

Requirement Analysis:

Purpose: The method determines a discount level for a Contact, which suggests it generates or modifies a recommendation (e.g., a discount offer).

Input: The method likely takes a List as input, where ContactWrapper is a custom class containing Contact data and other factors.

Output: Since this is for NBA, the method should return a List, where Recommendation is a standard Salesforce sObject used by NBA to represent suggested actions (e.g., a discount offer). The Salesforce Object Reference Guide confirms: “The Recommendation object represents a suggested action in Next Best Action, with fields like Name, Description, and ActionReference” (Salesforce Object Reference Guide, Recommendation Object).

Enhance Element Specifics: An Enhance Element typically expects a List as output for each input, not a nested List>, unless bulkified in a specific way. However, the method must support bulkification (taking a List as input and returning a List).

Evaluating the Options:

A.

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@InvocableMethod

global static List> getLevel(List input)

{ /*implementation*/ }

Accessibility: global static and @InvocableMethod are correct for an invocable method.

Input: List is appropriate, assuming ContactWrapper is a custom class with @InvocableVariable properties to pass Contact data.

Output: Returns List>, which is a nested list. The Apex Developer Guide notes: “An @InvocableMethod can return a nested List, but for Flow or NBA, the expected output is typically List for direct mapping” (Salesforce Apex Developer Guide, InvocableMethod Annotation). In NBA, an Enhance Element generally expects a List<Recommendation> to map directly to recommendations, not a nested list. A nested list (List<List<Recommendation>>) is more common in Flows when processing multiple outputs for multiple inputs, but for NBA, this is not the standard pattern for an Enhance Element.

Conclusion: Incorrect, as the nested List> return type does not align with the typical expectation of an Enhance Element in NBA, which expects List.

B.

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@InvocableMethod

global Recommendation getLevel(ContactWrapper input)

{ /*implementation*/ }

Accessibility: Uses @InvocableMethod and global, but the method is not static. The Apex Developer Guide states: “An @InvocableMethod must be static to be callable from Flow or Next Best Action” (Salesforce Apex Developer Guide, InvocableMethod Annotation). This results in a compilation error.

Input: Takes a single ContactWrapper, not a List. Invocable methods must support bulkification by taking a List as input, even if only one record is passed. The Apex Developer Guide specifies: “Invocable methods must take a List as input to support bulkification” (Salesforce Apex Developer Guide, InvocableMethod Annotation).

Output: Returns a single Recommendation, not a List. Similarly, the output must be a List to support bulkification.

Conclusion: Incorrect due to missing static keyword, and both input and output violate the bulkification requirement (must use List).

C.

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@InvocableMethod

global List> getLevel(List input)

{ /*implementation*/ }

Accessibility: Uses @InvocableMethod and global, but the method is not static, resulting in a compilation error (same issue as option B).

Input: List is correct for bulkification.

Output: Returns List>, which, as noted in option A, is not the typical return type for an NBA Enhance Element. It expects List to directly map to recommendations.

Conclusion: Incorrect due to missing static keyword and the nested List> return type, which is not ideal for NBA Enhance Elements.

D.

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@InvocableMethod

global static List getLevel(List input)

{ /*implementation*/ }

Accessibility: global static and @InvocableMethod are correct, making the method accessible to NBA.

Input: List supports bulkification and is appropriate for passing Contact data and factors.

Output: Returns List, which aligns with the expectation of an NBA Enhance Element. The Enhance Element can use the returned recommendations (e.g., discount offers) directly in the NBA strategy. The Salesforce Help documentation for Next Best Action confirms: “An Apex method invoked by an Enhance Element typically returns a List to provide or modify recommendations” (Salesforce Help, Next Best Action Enhance Element).

Conclusion: Correct, as it meets all requirements: proper accessibility, bulkified input/output, and the expected return type for NBA.

Why Option D is Correct:

Option D is correct because:

It uses @InvocableMethod, global, and static, making the method callable from a Next Best Action Enhance Element.

The input List supports bulkification and allows passing Contact data and other factors.

The output List matches the expected return type for an NBA Enhance Element, allowing the strategy to use the returned recommendations (e.g., discount offers) directly.

This aligns with Salesforce best practices for invocable methods in process automation, as outlined in the Apex Developer Guide and Next Best Action documentation.

Example for Clarity:

Here’s how option D might be implemented:

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global class DiscountCalculator {

@InvocableMethod(label='Get Discount Level' description='Determines discount level for a Contact')

global static List getLevel(List input) {

List recommendations = new List();

for (ContactWrapper wrapper : input) {

// Example logic to determine discount level

Decimal discountLevel = 0.1; // 10% discount based on factors

Recommendation rec = new Recommendation();

rec.Name = 'Discount Offer';

rec.Description = 'Offer a ' + (discountLevel * 100) + '% discount to ' + wrapper.contactName;

rec.ActionReference = 'ApplyDiscount'; // Reference to a Flow or action

recommendations.add(rec);

}

return recommendations;

}

}

global class ContactWrapper {

@InvocableVariable

global String contactName;

@InvocableVariable

global Id contactId;

// Add other factors as InvocableVariables

}

Usage in NBA: The Enhance Element in the Next Best Action strategy calls getLevel, passing a List with Contact data. The method returns a List, each representing a discount offer, which NBA can then present to the user.

Handling Typos:

The options are syntactically correct in the provided image, with no typos to address.

The question assumes ContactWrapper is a properly defined class with @InvocableVariable properties, which is a reasonable assumption for the context.

Option D’s ListRecommendation in the original question appears to be a typo (missing < and >). The correct syntax is List, as assumed in the analysis and corrected in the formatted options.