The correct answer is option B. has a defective allele and normal phenotype.
Explanation:
Genetic carrier or the hereditary carrier is an organism or a person that has a recessive allele for a particular trait or character (generally mutation) but does not exhibit the trait or any character related to the trait.
The carriers are normal in the sex-linked characters in comparison to the autosomal traits. Females are generally the carrier for sex-linked characters and carry the allele to the next generation.
Thus, the correct answer is option B. has a defective allele and normal.
In mammals, the powerful muscle that aids in breathing is the diaphragm. This muscle expands and contracts the chest cavity and forces air in and out of the lungs. Hope that helped =)
