Answer:
C. His mother carried at least one allele for that trait
Explanation:
-Men have a single allele of each gene on the X chromosome, inherited from their mother, and a single allele of each gene on the Y chromosome, from their father.
-A sex-linked trait is a trait that is controlled by a gene or an allele located on the sex chromosome.
-X-linked traits are maternally inherited from carrier mothers or from an affected father. Each son born to a carrier mother has a 50% probability of inheriting the X-chromosome carrying the mutant allele.
We all have the same genetic makeup. DNA
