What is the most likely cause of this failure?

Refer to the exhibit.

A network engineer is attempting to register a Cisco TelePresence endpoint to a Cisco VCS.

What is the most likely cause of this failure?
A . The lab.local SIP domain is not configured in the Cisco VCS allow list for registration.
B . The Cisco VCS failed to bind to the LDAP server, which is where the lab.local SIP domain is learned.
C . The lab.local SIP domain does not exist on the Cisco VC
E . The endpoint does not have the proper port assignments configured for SIP signaling.
F . The endpoint uses the TCP protocol and the Cisco VCS is configured to allow only TLS for SIP registrations.

Answer: C