口袋里有2个红球和2个黑球(形状、大小相同),摸到红球的可能性是请选择CBA3f-@*J,J0b0t8F)v.H+g*z/N1u
A.1/4+g*z/N1u
B.2/4+g*z/N1u
C.2/2+g*z/N1u
D .3/2+g*z/N1u