The correct answer is thesis statement. A thesis statement is the most important sentence in an essay - in it, you will find the main idea of the essay and why it was written in the first place. The author will briefly summarize his or her motivation and goal for writing the essay in this sentence, which is usually found at the end of the introductory paragraph.
It allows the reader to see how the character came to be who he or she is currently, it creates realism in the text, it creates tension between the narrator and the character, etc.
