What should me marketer do to prevent the subscriber from receiving further commercial messages?

When receiving spam complaints from recent email sends, a marketer from Northern Trail Outfitters (NTO) identifies an email address that has consistently marked promotional email messages from WTO as spam.

What should me marketer do to prevent the subscriber from receiving further commercial messages?
A . Use the complaint exclusion list on future sends.
B. Add the subscriber to the auto-suppression list.
C. Delete the subscriber from All Subscribers

Answer: B