The answer is C. people who are reading the story. Just like the audience of a movie is made up of the people watching the movie, the audience of literature is made up of the poeple who read the story.
Can you attach the entire article because it may be either A or D?
You are narrowing your topic. Since you already know your main idea, you must list specific details in relation to it. Then, you must choose one and elaborate on that one subject.
