A fossil of an extinct dinosaur is found, and the anatomy of the fossil shows similarities to that of a bird. What possibly explains these similarities?

A. This is purely chance and isn't significant.

B. The extinct dinosaur and modern bird share a common ancestor.

C. All dinosaurs evolved into birds and that's why there aren't any dinosaurs alive today.

D. Dinosaurs choose to fly, and evolved into birds to escape predation and capture food.