What is the proper syntax for enabling Cisco Express Forwarding (CEF)?

A.
router(config)# ip cef

B.
router(config)# cef ip

C.
router(config)# cef enable

D.
router(config-if)# cef ip enable

Explanation:

To enable CEF on the route processor card, use the ip cef global command in global configuration mode. To disable CEF, use the no form of this command:
– ip cef [distributed]
– no ip cef [distributed]
To enable CEF operation on an interface after the CEF operation has been disabled, use the ip route-chache cef command in interface configuration mode. To disable CEF operation on an interface, use the no form of this command.