Which three QoS mechanisms can be configured to improve VoIP quality on a converged network？（）
- AThe use of a queuing method that will give VoIP traffic strict priority over other traffic
- BThe use of RTP header compression for the VoIP traffic.
- CThe proper classification and marking of the traffic as close to the source as possible
- DThe use of 802.1QinQ trunking for VoIP traffic
- EThe use of WRED for the VoIP traffic