Ans: B
The required probability
The required probability
$\begin{array}{cl}
= & \dfrac{C^7_5}{C^{15}_5} + \dfrac{C^7_4 \times C^8_1}{C^{15}_5} + \dfrac{C^7_3 \times C^8_2}{C^{15}_5} + \dfrac{C^7_2\times C^8_3}{C^{15}_5} \\
= & \dfrac{9}{11}
\end{array}$
