Which three QoS mechanisms can be configured to improve VoIP quality on a converged  network？（）

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 for the VoIP traffic