Which statement about the Lightweight Access Point Protocol （LWAPP） is true？ （）

• 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.