Answer:
c. the summary of the paragraph's line of thought.
Step-by-step explanation:
A formal essay is a type of essay which is intended primarily to inform or persuade the audience. The structure of the essay comprises of an introduction, the body paragraphs and a conclusion to end with. The introduction is the most influential part of the essay which holds the mind of the reader to complete it. The end of the introduction is about the main idea of the essay. The body paragraphs include the details of the topic. The conclusion includes a summary of the thesis statement.