Your customer has asked you about changes necessary to their circuit-switched PBX to accommodate the upcoming Cisco Unity Unified Messaging installation. Their telephone system will use a PIMG integration to Cisco Unity. Other than possibly requiring software reconfiguration on the telephone system and the installation of the PIMGs, what do you tell the customer?

A.
The telephone system requires enough analog line cards to support the gateway units.

B.
Voice boards must be installed in the Cisco Unity platform.

C.
The gateway must be physically close to the Cisco Unity for the RS-232 cable to reach.

D.
Digital phone ports are required in the telephone system to support the gateways.