What is the service enumerated byjames in the above scenario?

Elante company has recently hired James as a penetration tester. He was tasked with performing enumeration on an organization’s network. In the process of enumeration, James discovered a service that is accessible to external sources. This service runs directly on port 21 .

What is the service enumerated byjames in the above scenario?
A . Border Gateway Protocol (BGP)
B . File Transfer Protocol (FTP)
C . Network File System (NFS)
D . Remote procedure call (RPC)

Answer: B