Which technology should Dr Billexplain to the executives?

Dr Billis a Security Administrator whose organization maintains several IKE VPNs. Executives in
Dr King’s organization want to known which mechanism VPN-1/FireWall-1 uses to guarantee the
authenticity of messages. Which technology should Dr Billexplain to the executives?

A.
Application Intelligence

B.
Certificate Revocation Lists

C.
Digital Signatures

D.
Hybrid Mode Authentication

E.
Key Exchange Protocols