Which of the following about LDP-over-RSVP is TRUE?

RSVP LSPs must exist between each PE-ABR pair, or ABR-ABR pair in each area.

When LDP-over-RSVP is active, the LDP prefixes are resolved to a physical egress interface.

Targeted sessions must exist between all routers along the tunnel path.

Link LDP sessions must exist between each ABR-ABR pair in each area.