Which Statement About MPLS LDP Router ID Is True

Which statement about MPLS LDP router ID is true?

A) If not configured, the operational physical interface is chosen as the router ID even if a loopback is configured.
B) The loopback with the highest IP address is selected as the router ID.
C) The MPLS LDP router ID must match the IGP router ID.
D) The force keyword changes the router ID to the specified address without causing any impact. The force keyword changes the router ID to the specified address without causing any impact.