In an 802.11n WLAN with a heterogeneous set of associated client devices including 802.11b, 11g, and
11n, what HT protection mode will the BSS use?

A.
Mode 0: No protection mode (Greenfield)

B.
Mode 1: Nonmember protection mode

C.
Mode 2: 20 MHz protection mode

D.
Mode 3: Non-HT mixed mode