Answer:
Claim is the correct answer.
Step-by-step explanation:
A claim is defined as stating something as true or false; it is important to mention it in the opening paragraph of an essay because it will help set the tone of the text and also it is a way to introduce the topic and get the reader's attention. This claim should contain the main idea of the essay and should be written in one sentence. Evidence, reason and supporting details come later, so they are incorrect.