Refer to the partial Cisco IOS XR configurations exhibit for Router 1 and Router 2.

There are two routers that are connected back to back over the Gigabit Ethernet link. If the “show
mpls ldp neighbor” command output on Router 1 does not show LDP peering with Router 2, what
could be the possible root cause of the LDP peering problem?

A.
missing interface under OSPF IGP configuration

B.
hello timers mismatch on Router 1 and Router 2

C.
password for LDP session mismatch on Router 1 and Router 2

D.
MPLS LDP session protection is not configured