Which statement about the Lightweight Access Point Protocol （LWAPP） is true？（）
- A LWAPP encrypts control traffic between the AP and the controller.
- B LWAPP encrypts user traffic with a x.509 certificate using AES-CCMP
- C LWAPP encrypts both control traffic and user data.
- D When set to Layer 3， LWAPP uses a proprietary protocol to communicate with the Cisco Aironet APs.