As defined in the 802.11 specification, legacy Power Save requires an inefficient back-and-forth frame
exchange process. Due to this inefficiency, many WLAN device implementations use a variation of 802.11
Power Save to accomplish the same function.
What non-standard power save behavior is used by most Wi-Fi devices in actual legacy Power Save
implementations?

A.
Client devices ignore the TIM field and automatically send PS-Poll frames after every beacon.

B.
After each beacon, the AP attempts to empty its frame buffer by sending Wake-on-WLAN frames to
wake each dozing client.

C.
Request-to-Send and Clear-to-Send frame exchanges are used to trigger the delivery of buffered data.

D.
The Beacon interval is changed from the default 100 time units to 10 or less time units.

E.
Clients send null data frames to the AP and switch the power management bit from 1 to 0 to receive
queued data.

F.
Stations send a CTS-to-self frame to the AP with a very long duration period so they can receive all of
their buffered data at once.