✅Comprehensive and Detailed Explanation:

Here’s the breakdown of what’s happening in this automation process:

The file is placed (encrypted) in the SFTP location.

File Transfer activity decrypts the file and moves it to the Safehouse.

Import File activity imports the data into a staging data extension.

Data Extract activity converts the DE to a format usable by All Subscribers (e.g., unsubscribe list extract).

File Transfer activity moves that extract file to a designated folder.

Final Import File activity uses that extract to unsubscribe subscribers from All Subscribers.

This full chain ensures secure file processing and proper unsubscription based on Subscriber Key.

❌Why Other Options Are Incorrect:

A. Lacks the initial File Transfer step to decrypt and move the encrypted file.

B & C. Include unnecessary Query activities that are not relevant for direct unsubscription processing from a clean unsubscribe file.

Exact Extracts from Salesforce Documentation:

File Transfer & Data Extract for Unsubscribe: "Use File Transfer activity to decrypt and move encrypted files into Safehouse. Use Import File and Data Extract to populate unsubscribe lists with Subscriber Keys."

— Source:https://help.salesforce.com/s/articleView?id=sf.mc_as_activities_file_transfer.htm

— Source:https://help.salesforce.com/s/articleView?id=sf.mc_as_data_extract.htm

All Subscriber List Management: "If your account uses Subscriber Key, the unsubscribed file must contain the Subscriber Key and can be processed using Data Extract and Import File activities."

— Source:https://help.salesforce.com/s/articleView?id=sf.mc_subscribers_all_subscribers.htm