[tex] P(B|A)=\dfrac{P(A \cap B)}{P(A)}\\\\
|\Omega|=15\cdot14=210\\
|A|=4\cdot14=56\\
|A\cap B|=4\cdot4=16\\\\
P(A)=\dfrac{56}{210}=\dfrac{4}{15}\\
P(A \cap B)=\dfrac{16}{210}=\dfrac{8}{105}\\\\
P(B|A)=\dfrac{\dfrac{8}{105}}{\dfrac{4}{15}}=\dfrac{8}{105}\cdot\dfrac{15}{4}=\dfrac{2}{7}\Rightarrow \text{A} [/tex]
