What command makes it possible to run MPLS/LDP in secure mode between P and PE?

What command makes it possible to run MPLS/LDP in secure mode between P and PE?

A.
Enable crypto/ipsec between PE and P

B.
mpls tdp neighbor x.x.x.x

C.
mpls neighbor ldp-peer x.x.x.x

D.
mpls ldp neighbor x.x.x.x