A company has a Frame Relay WAN with one central-site router and 100 branch office
routers. A partial mesh of PVCs exists: one PVC between the central site and each of the
100 branch routers. All routers use point-to-point subinterfaces and one subnet per PVC.
Which of the following is true about OSPF in this design?

A.
The central site router has 100 fully adjacent neighborships with the 100 branches.

B.
The central site router has neighborships with all branch routers, but fully adjacent
neighbors with only two branches.

C.
The central site router has a neighborship with the Frame Relay switcH.

D.
None of the other answers is correct.

Explanation:
Frame Relay is a Layer 2 service and as such does not participate in customer routing
protocols. Because the design uses a separate subnet per PVC, and one point-topoint
subinterface per PVC/subnet, OSPF will use a point-to-point network type.
That means that the two routers on either end of a PVC will become neighbors, and
become fully adjacent, meaning the central site router will have 100 fully adjacent
neighborships.