Well depending on the story, you could have asked all of em, but mostly you should use D) What will the readers reaction be to my story? because if this is a school thing, your teacher is going to be reading 30 of the (most likely) similar or same thing. or A) What was the purpose of my story, and did I achieve that purpose? Is because Teachers use a grading scale and they may use your story as an example to another class on what to do or what not to do, so you may want to be careful.
