what are these structures an example of?\no transitional structures\no analogous structures\no vestigial…

Brief Explanations:

Vestigial structures are remnants of organs or structures that had a function in an ancestor but are no longer functional or have a reduced - function in the current organism. Whales have pelvic and femur bones which are vestiges of the hind - limb structures of their land - dwelling ancestors.

Answer:

C. vestigial structures