What is the port number of the IPsec Encapsulating Security Payload packet?

A.
UDP port 50

B.
IP protocol 51

C.
TCP port 51

D.
TCP port 50

E.
IP protocol 50

F.
UDP port51

Explanation:
6.2. Managed Security services traversing the core
AH operates directly on top of IP, using IP protocol number 51.
ESP operates directly on top of IP, using IP protocol number 50.