Which of the following best describes the results of the research discussed in paragraph 4? A. Scientists used mathematical models to show that most of the extinctions occurred in areas where humans had recently arrived. B. Scientists established that the main population of North Americans who hunted lived in Canada during the time of the megafauna extinctions. C. Scientists used numerical models to confirm that a small population of humans could have caused big-game extinctions in a relatively short period of time. D. Scientists used statistics to prove beyond doubt the currently accepted view that human hunters were the main cause of the megafauna extinctions.