Three rotten apples are accidently mixed with fifteen good apples. Assuming the random variable \( x \) to be the number of rotten apples in a draw of two apples, the variance of \( x \) is:
\( \frac{40}{153} \)
\( \frac{37}{153} \)
\( \frac{47}{153} \)
\( \frac{57}{153} \)