What is one difference between Cisco inline power and 802.3af PoE?

What is one difference between Cisco inline power and 802.3af PoE?

A.
You must determine the total number of IP phones the switch can support with 802.3af to avoid oversubscription.

B.
Cisco inline power should only be activated for those ports that require PoE to avoid oversubscription.

C.
Cisco inline power provides a variable amount of power by using CDP.

D.
You must specify which set of pins the powered device is going to accept power on for 802.3af.