How is the Cisco Compatible Extensions S36 message used in Cisco WLC v7.0?

A.
AP initiates location information exchange with wireless clients.

B.
AP requests to wireless clients to actively probe only the currently active RF channel.

C.
AP requests to wireless clients to actively probe all channels.

D.
AP requests to wireless clients to passively probe all channels.

E.
AP messages are sent to other APs at various power levels.