The main idea I think is "But beyond that, most people know very little about this popular fungus."
I believe the correct answer is D because a theme can have multiple meanings and A is definitely wrong because that has nothing to do with the theme. B is wrong because just because the authors biography might say one thing but the story they wrote might be based off of something else. C is also wrong because if you take notes does not mean you will have the theme. I hoped I helped
Answer: it is the second option.
