Your customer has a requirement of a voice-mail-only system with redundancy/failover to service their 10,000 users in locations across Europe. They plan to create a new forest/domain for the Cisco Unity installation with Exchange servers for off-box message storage. They plan to install one Cisco Unity server with failover in Frankfurt, Berlin, and London. Telephone traffic at the London location at times exceeds the current Cisco Unity port capacity. They plan to use the failover server in London for overflow capacity.What do you tell the customer?

A.
This will work as planned.

B.
They need to purchase the license pooling feature.

C.
They need to install a second Cisco Unity server set in London.

D.
This will work if the SQL port synchronization feature is enabled.