Which statement indicates something that can cause an inbound PSTN call to an H.323 gateway that is configured in Cisco Unified Communications Manager to fail to ring an IP phone?

A.	The gateway is not registered in Cisco Unified Communications Manager.
B.	The gateway IP address that is configured in Cisco Unified Communications Manager does not match the IP address that is configured at the gateway in the h323-gateway voip bind srcaddr command.
C.	The Cisco Unified Communications Manager does not have a matching route pattern to match the called number.
D.	The gateway is missing the command allow-connections h323 to h323 under the voice service voip configuration.