TOEFL Listening: ETS-TOEFL听力机经 - 12O32458M3C941_TP$

Why does the professor mention a meteor that struck Earth during the time of the dinosaurs? A. To imply that that meteor impact also affect other large animals in North America B. To point out that Earth was often struck by meteors in the past C. To explain why it is to hypothesize that a similar impact could have caused a later extinction event D. To challenge a commonly accepted claim about dinosaur extinction