What identifies an MGCP endpoint?

What identifies an MGCP endpoint?

A.
A two part identifier that consists of thetelephone number and local name of the user.

B.
A two part identifier that consists of thetelephone number and remote name of the user.

C.
A two part identifier that consists of the domain name of the user and the IP address of the gateway.

D.
A two part identifier that consists of the local name of the user and the domain name of the gateway.