Which issue would cause an MGCP gateway to fail to register with Cisco Unified Communications Manager?

A.	missing the configuration command isdn bind-l3 ccm-manager under the ISDN interface
B.	mismatched domain name on the MGCP gateway and Cisco Unified Communications Manager gateway configuration
C.	misconfigured route group in Cisco Unified Communications Manager
D.	incorrect MGCP IP address specified in the gateway configuration in Cisco Unified Communications Manager