A couple has four children: two boys and two girls. One of the boys is affected by hemophilia and one of the girls is a carrier of the mutant allele for hemophilia (an X-linked recessive trait). Which of the following is most likely true?

• A. The mother and father are unaffected by hemophilia.
• B. The mother is affected and the father is unaffected by hemophilia.
• C. The mother is a carrier and the father is unaffected by hemophilia.
• D. The mother and the father are both carriers of the mutant allele.

Answer: (C)