Refer to the exhibit. Cisco Unified CallManager cluster A and Unity A use
extension range 1000-2500. Cisco Unified CallManager cluster B and Unity B use extension range 3000-3450. Cisco Unified CallManager cluster C and Unity C use extension range 4200-4400. Your customer wants to deploy Unified Messaging. Exchange stores are local at each site and part of the same organization. Digital networking without using access codes is an absolute requirement, and callers need to be able to use the Cisco Unity Auto Attendant to reach any user at any site.

Which statement is true?

A.
To deploy Unified Messaging, you need three separate dialing domains.

B.
Configure all Cisco Unity servers into the same dialing domain and each Cisco Unity call handler search scope to that dialing domain.

C.
Cisco Unity servers A and B are in the same dialing domain and Cisco Unity C uses extension masking to address any extension conflicts with them.

D.
All Cisco Unity servers will recognize each other via Active Directory. The Cisco Unified CallManager will handle any overlapping dial plan with partitions and calling search spaces.