Refer to the exhibit. The user of IP phone A has opened a trouble ticket that he cannot call IP
phone B. where is the best place for troubleshooting this issue.

A.
IP phone B

B.
The Cisco Unified Communication Manager system in the site A

C.
IP phone A

D.
IP phone A user

E.
The local VoIP voice gateway of IP phone B

F.
IP phone B user