How should journey Builder be configured to meet this requirement?

Northern Trail Outfitters (NTO) receives a daily file drop of customers who have made recent purchases. NTO would like to send out a thankyou’ email the first time they Show up it the file drop.

How should journey Builder be configured to meet this requirement?
A . Configure Journey Settings to ‘allow no re-entry.
B. Configure Journey Email Send to dedupe on email address.
C. Configure Journey Entry Event to ‘allow no re-entry.’

Answer: A