The requirement is to identify an OmniScript element that enables users to choose from a dropdown list. In Salesforce OmniStudio, the Select element is specifically designed for this purpose, making A the correct answer.

Here’s why A. Select is the correct answer:

Select Element Overview: The Select element in OmniScript creates a dropdown list (or similar UI control like a radio button group, depending on settings) that allows users to pick one option from a predefined set. It’s a user-facing input element that supports:

Manual Options: Hardcoded values entered in the designer.

SObject Options: Values retrieved from a Salesforce field (e.g., picklist values).

DataRaptor/Custom Options: Dynamic values from a DataRaptor Extract or Apex.

Dropdown Functionality: By default, when configured as a “Dropdown” in the Style settings, the Select element renders as a dropdown menu, enabling users to choose from a list (e.g., selecting a Case Priority like "High," "Medium," "Low").

Meeting the Requirement: The Select element directly fulfills the need for a dropdown list, providing a simple, interactive way for users to make a selection within an OmniScript.

Now, let’s examine why the other options are incorrect:

B. Calculation Action: A Calculation Action performs backend computations or data manipulations (e.g., multiplying values or setting variables). It’s not a UI element and doesn’t present a dropdown list for user interaction.

C. Lookup: The Lookup element allows users to search for and select a Salesforce record (e.g., an Account) via a searchable popup. While it involves selection, it’s not a dropdown list—it’s a dynamic search interface that returns a record, not a predefined list of options.

D. DataRaptor Extract Action: This action (correcting the typo "Data Mapper Extract Action") retrieves Salesforce data using a DataRaptor Extract, but it’s a backend process, not a UI element. It can supply data to a Select element for a dropdown, but it doesn’t enable user selection itself.