Answer:
D. The person who tells the story
Explanation:
The narrator is the person telling the story, or the voice that an author takes on to tell a story.
The person who reads the story is simply a reader. They aren't narrating.
Someone who says all of the dialouge isn't a narrator either, because only saying the dialouge excludes the rest of the story. It's not telling the story.
The person who writes the story is the author, not the narrator.
Therefore, option D makes the most sense.
hope this helps!