Which two of these statements regarding Authentication Header (AH) are true?(choose two)

A.
AH requires the use of Encapsulation Security Payload (ESP) to work correctly

B.
AH provides authentication for most of the "outer" IP header, as well as the upper layer protocols

C.
AH can be deployed in tunnel mode only

D.
AH is not commonly used, because it can only encrypt the original packet using a DES encryption algorithm.

E.
AH will work through a NAT (one-to-one) device, but not through a PAT(one-to-many) device

F.
AH use an IP protocol number of 51