In a family of six members A, B, C, D, E, and F, there are two males and four females. A is a teacher, B is a doctor, C is the sister of D, D is the brother of E, and F is the mother of A. Who among the following is a male?
Answer: B. B
B is identified as a doctor, and since there are only two males in the family, B must be one of them.