单项选择题

A. LWAPP encrypts both control traffic and user data.
B. LWAPP encrypts user traffic with an x.509 certificate using AES-CCMP.
C. When set to Layer 3, LWAPP uses a proprietary protocol to communicate with the Cisco  Aironet APs.
D. LWAPP encrypts control traffic between the AP and the controller.
E. None of the other alternatives apply.