Identifying and handling duplicate entries during data cleansing for case migration involves multiple strategies to ensure data integrity. Matching and merging records based on common identifiers like email addresses or phone numbers is effective in eliminating duplicates. Data quality rules and duplicate detection tools can systematically flag potential duplicates for further review. Manually reviewing case details provides a final check to ensure no duplicates slip through. Hence, "D. All of the above, depending on the complexity and desired level of automation for duplicate case handling" covers all necessary methods for thorough duplicate management.
Reference: Salesforce Data Management