What WLAN Layer 2 security must be selected to use client MFP?

Correct Answer: C
Explanation/Reference:
Explanation: In 802.11, management frames such as (de)authentication, (dis)association, beacons, and probes are always unauthenticated and unencrypted. In other words, 802.11 management frames are always sent in an unsecured manner, unlike the data traffic, which are encrypted with protocols such as WPA, WPA2, or, at least, WEP, and so forth.
Reference: http://www.cisco.com/c/en/us/support/docs/wireless-mobility/wlan-security/82196-mfp.html#climfp