Your answer would be C. Hope this helps!
Hmmm... Either A or D, but I'm not sure. I know for a fact that B and C are her motives, but A and D are quite similar
<span>The answer is the option A. The naturalist. He is the person who performs the action. The actions is indicated by the verb. The verb is realized, Then you can ask who realized that the orchids had adapted to attract insects? The answer to who performs the action will reveal the subject. IN this case the answer is the narutalist. Which means that the subject is the naturalist.</span>