Refer to the exhibit. With an IPSec tunnel established between remote Router A and head-end router B, how can the Service Provider Edge Router identify Voice over IP packets flowing through the IPSec tunnel from a Cisco 7960 IP phone?（）

• A、UDP ports 16384 through 32727
• B、ESP packets less than 113 byes
• C、DiffServ codepoint EF Expedited Forwarding
• D、RTP ports 6970 through 6999