Which statements are true regarding an IEEE 802.11 frame’s PLCP preamble?

A.
A long preamble uses a Sync field of 128 bits, and both stations and access points may use either long or short preambles.

B.
A short preamble uses a Sync field of 40 bits, and stations and access points must have matching preamble lengths in order to communicate.

C.
Long and short preamble lengths vary depending on the modulation in use on the network, and access points always inform stations of the preamble length in use on the network.

D.
When short preambles are being used, the Sync and SFD fields both consist of 16 bits. Only access points have configurable preamble lengths.

E.
An HR-DSSS access point that supports both long and short preambles may allow stations that are using different preamble lengths to communicate through it simultaneously.

F.
ERP client stations associating to HR-DSSS access points must use the preamble length specified by the access point.