A bag contains 5 white marbles and 5 black marbles. If each of 5 girls and 5 boys randomly selects and keeps a marble, what is the probability that all of the girls select the same colored marble? Choose one:
A) 1 / 126 B) 1 / 120 C) 1 / 24 D) 4 / 25 E) 1 / 2

Rationale: "consider a case when all girls select black marbles . . . so girl 1 will chose 1 black marble out of 10 . . and black marble will be chosen from 5 black marbles girl 1 will have a probability of picking black marble 5 / 10 girl 2 will have to pick a black marble out of 4 and total remaining no . of marbles 9 = 4 / 9 so we have probability of all girls selecting black marbles as 5 / 10 * 4 / 9 * 3 / 8 * 2 / 7 * 1 / 6 = 1 / 252 since girls can also select white marbles so we will have 2 cases so probability of girls selecting all same colour marbles is 2 * 1 / 252 or 1 / 126 ans is a"
Answer: A