Answer:
A. homologous structures.
Step-by-step explanation:
Divergent evolution leads to the development of the evolution of homologous structures in closely related species. These structures have a common basic plan but are adapted to perform different functions according to the habit and habitat of the organism.
Fins of whales and human arms have common basic origin but are adapted to serve in swimming and holding things since whales are aquatic mammals but the human is not. Hence, they are homologous organs.