Answer: c. sperm cell
Explanation:
A germline mutation is the one which results in the fully developed germ cells (sperms or ovum) of the organism. Mutations occurring in these cells are the only mutations which are passed from the parents to their offsprings by sexual mode of reproduction involving the fusion of the male and female germ cells.
In the given situation the germline mutation will occur in the sperm cells of the deer, this mutation will be passed to the next generation of the deer by the sexual mode of reproduction. This mutation will be capable to alter the genetic make up of the entire population.
