Which two statements about the functionality of a gatekeeper are true? (Choose two.)
A.
Cisco Unified Communications Manager has gatekeeper functionality built in.
B.
Cisco Unified Communications Manager registers with a gatekeeper via SIP.
C.
Cisco Unified Communications Manager registers with a gatekeeper via H.323.
D.
A gatekeeper can enable CAC and AAR.
E.
A gatekeeper can enable CAC, but not AAR.