Answer:
The correct answer is "A single gene is responsible for pigmentation and hearing".
Step-by-step explanation:
A gene that is pleiotropic affects the phenotype at different traits. One example of pleiotropic gene is found on cats, where a single gene is responsible for pigmentation and hearing. There is still no scientific consensus of how the gene affects the two traits, but there is evidence in mice that suggest that the gene that affects pigmentation affects the maintenance of fluids in ear canals.