Explanation:
In sex-linked recessive inheritance (for example X-linked recessive), the incidence of the trait is much higher in males than in females. In fact, heterozygous females do not usually express the disease. In this case, the mutant allele is never transmitted directly from a father to his boy. The mutant allele can be transmitted through a series of female carriers. In these cases, affected males in a family group are all related to females.
Now, consider the following pedigree:
According to the definition of Sex-linked recessive, we can conclude that the correct answer is:
Answer:
