9. There are six balls in a box, among which there are two red, two green, and two yellow balls. Carol randomly takes two balls from the box, then Claudia also takes two balls, and finally Cheryl takes the remaining two balls. What is the probability that the two balls Cheryl takes are of the same color? ( ).
(A) $\frac{1}{10}$
(B) $\frac{1}{6}$
(C) $\frac{1}{5}$
(D) $\frac{1}{3}$
(E) $\frac{1}{2}$
9. C.

Notice that, the probability of the three people drawing balls is equal, regardless of the order of drawing, so we can let Cheryl draw first. The probability that the two balls she draws are of the same color is
$$
P=\frac{6}{6} \times \frac{1}{5}=\frac{1}{5} .
$$