Which of the following represents the exposition stage of this story?
a. the scene is set for a party at the shepherd's home.
b. the first stranger appears and converses with the hosts.
c. the second stranger reveals his grisly line of work.
d. the ultimate mystery of the story is uncovered.

The one that represents the exposition stage of the story is A, because it sets up the scene with the setting (shepherds home).  B is incorrect because this is apart of the rising action, what happens after A is already introduced, so the first stranger has relevance to arrive.  C is incorrect because something is being revealed, which is always part of the rising action.  And D is incorrect because the ultimate mystery in uncovered, which is the climax. :)