if the

Question:
If $\mathrm{P}(\mathrm{A})=\frac{1}{2}, \mathrm{P}(\mathrm{B})=0$, then $\mathrm{P}(\mathrm{A} \mid \mathrm{B})$ is

(A) 0 (B) $\frac{1}{2}$

(C) not defined (D) 1

Solution:

It is given that $\mathrm{P}(\mathrm{A})=\frac{1}{2}$ and $\mathrm{P}(\mathrm{B})=0$