Which two statements are true about traffic shaping and traffic policing？（） A: both traffic shaping and traffic policing cause retransmissions of connection-oriented protocols such as TCP B: both traffic shaping and traffic policing support the marking and re-marking of traffic C: the effects of traffic shaping and traffic policing when configured on a router are applied to outgoing traffic D: traffic shaping queues excess traffic whereas traffic policing discards excess traffic E: traffic shaping allows the traffic to exceed the bit rate whereas traffic policing prevents the traffic from exceeding the bit rate