A customer has Cisco IOS Firewall deployed. Even though the customer has FTP inspection enabled. Inspection doed not appear to be working for FTP services running on a non-standard port of 21000.Which feature can the customer enable to help resolve this?

A.
Cisco IOS Flexible Packet Matching

B.
Firewall Application Inspection and Control

C.
Firewall Application Layer Gateway

D.
Port-to- Application Mapping