You have been task to list the interfaces on which the OSPF protocol is enabled. Which of the following command will you type?

(A) show ip ospf brief
(B) show ip ospf interface brief
(C) show ip interface brief
(D) show ospf interface brief

show ip ospf interface brief is the correct answer. The command show ip ospf interface brief lists the interfaces on which the OSPF protocol is enabled (based on the network commands), including passive interfaces.