If you remember that exposition in a short story is at the beginning of the story and is where the author sets up the setting and the main characters in the story, this question will be easier for you. Knowing that this is an Edgar Allan Poe story would suggest a dark setting with questionable characters who may be caught in a web of deceit of some kind. The exposition ends where the reader begins to follow the rising action of this story with the first step into the action. Look at the story you have, look at who is introduced and at the setting of where the story takes place. Once you have those in place, look at the first step you take in finding out what is going to happen in this story. Now you are at the end of the exposition.