单项选择题
A.Cb20,2.0B.Cb20,1.5C.Cb25,2.0D.Cb25,1.5
A.Mb5,M5B.Mb7.5,M7.5C.Mb5,M7.5D.Mb10,M5
A.Mb5,Mb7.5B.Mb10,Mb7.5C.Mb7.5,Mb7.5D.Mb7.5,Mb10