TOEFL Listening: TPO-TOEFL听力TPO - 4Z2IT38I4N9EUQ99R$

What topic related to the Nightcap Oak does the professor mainly discuss? A. Factors that relate to the size of the area in which it grows B. The size of its population over the last few centuries C. Whether anything can be done to ensure its survival D. Why it did not change much over the last one hundred million years