Answer:
The correct answer is - that They share a common ancestor.
Step-by-step explanation:
The bones of forelimbs of whale, bat, cat, and human are similar in structure due to the fact they are homologous organs. Such organs which have the same basic structure but play a different role in their respective bodies are called homologous organs.
These organs are developed from the same organization during their development but due to evolutionary change in their environmental condition and their requirement, these organs are modified to perform different functions. The homologous structures are end result of divergent evolution which means they show common ancestry.