What should you do so that incoming calls can reach endpoints that are associated with a specific E.164 address?

A customer has a small group of users who do interactive video teaching from H.323 endpoints to H.320 videoconferencing systems. What should you do so that incoming calls can reach endpoints that are associated with a specific E.164 address?

A.
Configure the DID in the Cisco CallManager

B.
Deploy an IPCC server and configuration an IVR to act as a front end to the MCU

C.
Enable the DID capability that is built into the gateway

D.
Deploy the Cisco IP IVR