Question

A and B are events with Pr(B) > 0 Then Pr(A|B) =
a) Pr(A)/Pr(B) if B ⊆ A
b) Pr(A)Pr(B) if B ⊆ A
c) Pr(B)/Pr(A) if B ⊆ A
d) Pr(A) + Pr(B) if B ⊆ A