Answer:
Birds and Crocodiles (Ans. D)
Explanation:
Birds and Crocodiles shows most recent common ancestor because they are part of much larger group known as Archosauria (ruling lizards). When they both species divided from each others, they divided into 2 major evolutionary pathways:
The bird-line archosours , and the second one is crocodile-line archosours (which includes crocodilians and their ancestors).
So, Crocodiles are the closest living relatives of the birds and they sharing the most common ancestor.