What security weakness is present in pre-RSNA systems using 802.1X with dynamic WEP?

A.
There is no ability to authenticate individual users.

B.
The session key is crackable if enough traffic is transmitted using the key.

C.
All versions of EAP used with dynamic WEP pass the username across the wireless medium in clear text.

D.
APs automatically downgrade the security level to standard WEP if the wireless client device does not support dynamic WEP.