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?

The mother and father are unaffected by hemophilia.

The mother is affected and the father is unaffected by hemophilia.

The mother is a carrier and the father is unaffected by hemophilia.

The mother and the father are both carriers of the mutant allele.