An OSPF neighbor between routers R1 and R2 is stuck in loading state on R2. What are two
causes? (Choose two.)

A.
OSPF is not enabled on the interfaces.

B.
A firewall filter is blocking OSPF hellos on both sides.

C.
The R1 router has received a corrupted link-state request packet.

D.
The interface MTU is mismatched between the routers.