How does a PE-router operating in the default frame mode distribute labels?

A.
The PE-router distributes a label for every destination in its FIB.

B.
The PE-router only distributes labels for destinations inside the MPLS domain.

C.
The PE-router only distributes labels for destinations outside the MPLS domain.

D.
The PE-router does not distribute labels. Label distribution is only done by the core LSR.