** answer asap andd you dont have to give me a reason of why its correct just give me the correct
some mammals and reptiles survived the cretaceous extinction. why did mammals become widespread and successful during the cenozoic era?

a.
mammals could eat a variety of foods, including plants and meat.

b.
mammals had adaptations that them thrive in cold weather.

c.
mammals could grow very large, much larger than reptiles.

d.
mammals were already diverse and numerous when the cenozoic era began.