Which process should the consultant utilize for a reliable send method?

Northern Trail Outfitters wants to send an email to one million contacts in Sales Cloud. The criteria to segment contacts include using 10+ fields to segment.

Which process should the consultant utilize for a reliable send method?
A . Query Synchronized Data Extensions using a query activity to a Salesforce Data Extension, then send via Email Studio Send Flow
B. Import Salesforce Report through an import activity to a Salesforce Data Extension, then send to data extension using Email Studio email send
C. Assign the one million contacts from the report to a Salesforce campaign, and use a Single Step journey with Salesforce Campaign as an entry event
D. Send to a Salesforce Report from Marketing Cloud using Email Studio Send Flow

Answer: A