单项选择题
A.80B.160C.200D.210
A.5880种B.2940种C.1960种D.490种
A.90%B.81%C.70%D.68%
A.1200B.3600C.4800D.7200
A.12种B.5种C.9种D.7种
A.10B.12C.6D.8
A.72B.75C.78D.81
A.52B.64C.72D.74
A.3B.5C.7D.9
A.18B.15C.12D.10
A.2B.4C.5D.8