There are two Active Directory forests: AB.com and C.com. The Cisco Unified CallManager cluster A and Unity A use extension range 1000-2500. The Cisco Unified CallManager cluster B and Unity B use extension range 3000-3450. Both sites A and B are in AB.com. The Cisco Unified CallManager cluster C and Unity C use extension range 4200-4400. Site C is in C.com. Your customer wants to deploy unified messaging. Exchange stores are local at the sites. Digital networking without using access codes is an absolute requirement.What is the best solution?

A.
Site C needs to have all the servers reinstalled as part of AB.com.

B.
A unique dialing domain is created per Cisco Unity location. There is no requirement for one directory.

C.
A completely unique dialing location is created in Cisco Unified CallManager. Cisco Unity is assigned to that location.

D.
Future growth is accommodated by allowing all Cisco Unity servers to be in different forests, but to be part of the same dialing domain.