How would they set up the Import Activity to know the name of the file?

Northern Trail Outfitters wants to set up an automation that imports a file and sends an email to the contacts when the file is dropped on the SFTP. The name of the file will change, though it will always start with thankyou_customers.

How would they set up the Import Activity to know the name of the file?
A . Set File Naming Pattern to %%AUTOMATED_FILENAME%%
B. Set File Naming Pattern to %%BASEFILENAME_FROM_TRIGGER%%
C. Filename is automatically passed to Import Activity with File Drop Automations
D. Check the ‘Use filename from Automation’ checkbox

Answer: B