Voice quality is bad due to high delay and jitter on a link. Which two actions will improve the quality  of voice calls？（）

• A、Increase the queue size of the voice class.
• B、Guarantee bandwidth during congestion to the voice class with a bandwidth command.
• C、Increase the tx-ring of the egress interface.
• D、Implement LLQ for the voice class.
• E、Decrease the rx-ring of the egress interface.
• F、Decrease the queue size of the voice class.