Which is the MAIN advantage of having an application gateway?

Which is the MAIN advantage of having an application gateway?

A.
To perform change control procedures for applications.

B.
To provide a means for applications to move into production.

C.
To log and control incoming and outgoing traffic.

D.
To audit and approve changes to applications.

Explanation:
“An application-level gateway firewall is also called a proxy firewall. A proxy is a mechanism that
copies packets from one network into another; the copy process also changes the source and

destination address to protect the identity of the internal or private network. An application-level
gateway firewall filters traffic based on the Internet service (i.e., application) used to transmit or
receive the data.” – Shon Harris All-in-one CISSP Certification Guide pg 92