Refer to the exhibit.

The user of IP phone A has opened a trouble ticket stating that he cannot call IP phone B. Where
is the best place to start troubleshooting this issue?

A.
IP phone B

B.
the Cisco Unified Communication Manager system in site A

C.
IP phone A

D.
lP phone A user

E.
the local VoIP voice gateway of IP phone B

F.
IP phone B user

Explanation: