Which three WLAN statements are true?

Which three WLAN statements are true? (Choose three)

A.
A lightweight AP receives control and configuration from a WLAN controller to which it is associated.

B.
A wireless client operating at a lower data rate in a particular WLAN will delay all clients in that same WLAN

C.
Ad hoc mode allows mobile clients to connect directly without an intermediate AP.

D.
Another term for infrastructure mode is independent service set (IBSS).

E.
The Aironet 1230 access point is an example of an access point that operates solely as a lightweight access point.

F.
WLANs are designed to share the medium and can easily handle an increased demand of channel contention.

Explanation:

Lightweight access points first search for a WLAN controller using LWAPP in Layer 2 mode. Then the access point searches for a WLAN in Layer 3 mode. The control traffic between the access point and the controller is encapsulated with the LWAPP. The control traffic is encrypted via the Advanced Encryption Standard (AES). Lightweight APs need configuration and control information from a WLAN controller Incorrect Answers:
D: Ad hoc mode: This mode is called Independent Basic Service Set (IBSS). Mobile clients connect directly without an intermediate access point

Original answer B. A WLAN client that is operating in half-duplex mode will delay all clients in that WLAN. – I think there is error in question

http://www.cisco.com/en/US/docs/wireless/technology/1140/deployment/guide/1140dep.html
The problem with clients operating at low data rates (example, 1Mbps) is that each packet takes up more `airtime’ compared to clients utilizing high data rates such as 36Mbps to 54Mbps. In simpler terms, a client utilizing a 1Mbps rate is essentially `talking’ slower than other clients and therefore drags down aggregate performance. Since WLANs operate with the guideline that only one device, be it AP or client, can utilize the channel at any one moment, overall system performance drops when a large percentage of low data rate frames monopolize the airtime. By designing Access Point density for capacity and disabling lower data rates, aggregate system capacity can be increased.