Answer:
The correct answer is option D. a mutation in sex cells.
Explanation:
Sexual reproduction is the process in which new organisms are produced from the fusing or fertilization of the nucleus of a male sex cell and a female sex cell. Sex cells are also known as gametes.
Germinal mutations are those that occur in the egg or sperm cells and therefore can be passed on to the organism's offspring.
Mutation in A DNA that takes place in sex cells can be passed to offspring through sex cells. It can lead to genetic disorders such as sickle cell anemia.
Thus, the correct answer is option D.