Which of the following statements about CQ policy are correct?
选项：

A:CQ can assign different bandwidths for different services;
B:CQ can assign bandwidths for packets of different services according to bandwidth percentages. When packets of some types are not available, it will automatically increase the bandwidths for existing packet types;
C:The shortages of CQ are it needs configuring and the processing speed is slow;
D:None of above.