The correct answers are B. Upload the lead list using the Import Wizard and select a Matching Type to prevent duplicate lead creation and D. Utilize a Lead Matching Rule and corresponding Duplicate Rule to block newly created duplicate leads.

For 400 leads, the Data Import Wizard is appropriate because Salesforce supports importing leads and other common objects with the wizard, and it can handle up to 50,000 records.

Salesforce documentation for lead imports states that choosing a matching type sets criteria for avoiding duplicate leads when using the Data Import Wizard.

Duplicate Management also uses matching rules and duplicate rules to identify and control duplicates. Salesforce states that duplicate rules can block users from creating duplicate records, including lead duplicates.

Why others are incorrect:

A is incorrect because Data Loader’s update operation updates existing records and normally requires record IDs or proper matching/upsert configuration; it is not the best duplicate-prevention answer here.

C is not the correct Salesforce setup wording. The correct tools are Lead Matching Rules and Duplicate Rules.

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