What is called the access protection system that limits connections by calling back the number of
a previously authorized location?

A.
Sendback system

B.
Callback forward systems

C.
Callback systems

D.
Sendback forward systems

Explanation:
“Callback systems provide access protection by calling back the number of a
previously authorized location, but this control can be compromised by call forwarding.” Pg 48
Krutz: CISSP Prep Guide: Gold Edition.