Which statement is correct concerning dinosaur paleontologists understanding of their metabolism?

A$)$ They were warm$-$blooded.

B$)$ They were first viewed as warm$-$blooded followed by cold$-$blooded. Today we understand that they probably had a diverse and complex metabolism.

C$)$ They were cold$-$blooded.

D$)$ They were first viewed as cold$-$blooded followed by warm$-$blooded. Today we understand that they probably had a diverse and complex