单项选择题
A.Ω={1,2,3,4,5,6,7,8,9,10,11,12} B.Ω= C.Ω={2,3,4,5,6,7,8,9,10,11,12} D.Ω={1,2,3,4,5,6}
A.A=B B.AB C.AB D.AB