b.informational essay; details that support the main idea
Explanation:
The question itself explains it: <em>"the purpose is to show your knowledge about endangered animals"</em>.
An Informational essay is meant to deliver factual unbiased information. It can be the product of research or personal observation. Since the teacher is not to be convinced or humored and also, there's no problem to solve. Informational Essay is the correct option.
