Lets use process of elimination to find the answer to this question. It's not the third option because giving descriptions of time and place only help establish the setting of the story and theme is the main idea of the story, it wouldn't be the first option because the readers knowledge develops as the story goes on so they wouldn't be developing details from the story that help create the theme. It also wouldn't be the second option because the authors motivation is before the story was even wrote. Therefore the answer is option four "character motivation and plot" because it helps the reader learn from the characters of the story.
