The correct answer is C). Reading specifically to find the rising and falling actions of the story is not a way to acquire background knowledge about the cultural context of a text.
Paying attention to the rising and falling actions, which lead up to the climax and come right after the climax respectively, will only provide the reader with information about the story itself, that is, they will not provide information related to the cultural context of that story. Cultural context refers mainly to the type of society in which the characters live, their culture and how these factors influence the way they behave. On the other hand, footnotes, introductory materials, pictures, graphs and other textual aids generally offer the readers background information about the context that might be unknown for them.