What is the likely cause of the issue?

Refer to the exhibit.

An H.323 endpoint that is registered to Cisco VCS Control is not able to make B2B calls. Calls to other internal endpoints are working fine.

What is the likely cause of the issue?
A . The Conductor
B . 323 zone is set to "Off“
C . The Production CUCM
D . 323 zone is set to "Off”.
E . The Traversal Zone
F . 323 zone is in a "Failed" state
G . The Traversal Zone
H . 323 zone is set to "Off”

Answer: D