c) option is correct
Step-by-step explanation:
Heritable variations comes from mutations
Mutations are the initial cause of new heritable traits, if we take an example of a rabbit which can't choose to have a different fur color
Rather, a genetic mutation causes a difference in fur color, which may help that rabbit hide better in its environment
Mutation is one of the causes of natural selection as a result only superior genotype is favored and inferior genotype is eliminated