さらにMath

Two canoe riders must be selected from each of two groups of campers. One group consists of three men and one woman, and the other group consists of two women and one man. What is the probability that two men and two women will be selected?
(A) 1/6 (B) 1/4 (C) 2/7
(D) 1/3　(E)　1/2

答えはEなのですが、問題の意図がつかめません。
男女どの確率を求めたらよいのでしょうか？