Which QoS preclassification option will require the use of the qos pre-classify command for the VPN traffic？ （）

• A、VPN traffic needs to be classified based on the Layer2 header information
• B、VPN traffic needs to be classified based on the IP precedence or DSCP
• C、VPN traffic needs to be classified based on IP flow or Layer 3 information， such as source and destination IP address
• D、VPN traffic with Authentication Header （AH） needs to preserve the ToS byte