Why does the professor mention the size of the Nightcap Oak population over the last few hundred years A. to explain why it is likely the Nightcap Oak population will increase in the future B. to point out that Nightcap Oak's limited reproductive success has not led to a decrease in its population C. to present evidence that the Nightcap Oak is able to tolerate major changes in its environment D. to point out that the Nightcap Oak is able to resist diseases that have destroyed other tree species