An administrator types in the command router ospf 1 and receives the error message:
“OSPF process 1 cannot start.” (Output is omitted.) What should be done to correctly set up
OSPF?

A.
Ensure that an interface has been configured with an IP address.

B.
Ensure that IP classless is enabled.

C.
Ensure that the interfaces can ping their directly connected neighbors.

D.
Ensure that an interface has been configured with an IP address and is up.