What did the main character(characters) learn from the story. That is your theme.<span />
Expository writing is used to convey factual information (as opposed to creative writing, such as fiction). It is the language of learning and understanding the world around us. If you've ever read an encyclopedia entry, a how-to article on a website, or a chapter in a textbook, then you've encountered examples of expository writing
So a or d but i'm leaning toward d
