Given:

During 802.1X/LEAP authentication, the username is passed across the wireless medium in clear text.
From a security perspective, why is this significant?

A.
The username is needed for Personal Access Credential (PAC) and X.509 certificate validation.

B.
The username is an input to the LEAP challenge/response hash that is exploited, so the username must be known to conduct authentication cracking.

C.
4-Way Handshake nonces are based on the username in WPA and WPA2 authentication.

D.
The username can be looked up in a dictionary file that lists common username/password combinations.