Answer:
A. first-person narrator; a first-person narrator is the main character in a story, so he or she knows everything that happened or will happen in the narrative
Step-by-step explanation:
If Monroe wants to write a short story in which the narrator knows things the characters in the story don't, he should make use of first person narration.
This is because, in first person narration, the narrator recounts events using personal pronouns such as "I", "We", etc to show that he is narrating from his point of view which other characters in the story does not know about.