Which two wireless security statements are true？（）

A.A TACACS+ server is required to implement 802.1x.

B.MIC protects against man-in-the-middle and replay attacks.

C.The 802.1x standard provides encryption services for wireless clients.

D.The AES （symmetric block cipher） is specified in the IEEE 802.11i specification.

E.The IEEE 802.11i specification uses RC4 as its encryption mechanism.

F.WPA requires TKIP and AES as encryption methods.