Dogs have a reduced nonfunctional digit on their paws known as a dewclaw. What is this an example of?

C. Vestigial structure is the correct answer

Dogs have reduced non-functional digit on their paws known as dewclaw, this is an example of a vestigial structure. A vestigial structure is an anatomical structure which seems to have no function in the present organism but which was functional in the previous generation of the same organism.