Which QoS mechanisms can you use on a converged network to improve VoIP quality？（）

• A、The use of a queuing method that will give VoIP traffic strict priority over other traffic
• B、The use of RTP header compression for the VoIP traffic
• C、The proper classification and marking of the traffic as close to the source as possible
• D、The use of 802.1QinQ trunking for VoIP traffic
• E、The use of WRED