A.1/2-F(a) B.1/2+F(a) C.2F(a)-1 D.1-F(a)
A.P(AB)=0 B.P(AB)=P(A) C.P(A)+P(B)=1 D.P(AB)=P(A)P(B)
A.0<λ<1,且b=1-λ-1 B.0<λ<1,且b=λ-1 C.0<λ<1,且b=λ-1-1 D.0<λ<1,且b=1+λ-1