Supporting details can do all of the enlisted options except introduce the main idea. Supporting details are there to support the main idea, so of course they cannot introduce it. They are the result of the main idea, not its creator.
What are the examples of the rhetorical devices?
The answer is: A. to point out details the character would not notice.
The first-person point of view is a literary device that allows readers to get to know that character's thoughts, feelings and motives. Because the narrator refers to himself with words like <em>I, me, my </em>and <em>mine</em>, the story is seen through his or her eyes. As a consequence, it is not impartial and it may suggest features which are unknown or unnoticeable to the narrator. For example, they might not realize they have a psychological condition.
