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 thank you_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