In an 802.11n 2.4 GHz BSS, what prevents each station from using the full network bandwidth
(e.g. 130 Mbps) when multiple clients are actively exchanging data with the AP? (Choose two)

A.
Radio receiver hardware cannot process data as quickly as it can be transmitted.

B.
Half of the bandwidth is allocated to uplink traffic and half to downlink traffic.

C.
The DCF and EDCA coordination functions require backoff algorithms

D.
WLAN devices cannot detect collisions and must receive positive frame acknowledgment.

E.
WLANs rely on the CSMA/CD protocol and must wait a collision detection period after each
frame is transmitted.