The options are incomplete and have been listed incorrectly. Complete question has been attached.
Answer:
C) Dd and Dd
Explanation:
It is given that deafness is a recessive trait which means that Dr. Smith has genotype dd since a recessive trait can only be expressed when both the alleles in genotype are recessive. However, his parents are normal. So his parents can have DD or Dd genotype. Dr. Smith has obtained one recessive d allele from his father and other recessive d allele from his mother. Thus, the parents should have Dd genotype and the correct option is c.
