The correct answer is A. Two characters wearing masks at a costume party meet, have a brief conversation, and go their separate ways. Each believes that the other is a stranger, but the reader knows that they're good friends.
Step-by-step explanation:
Dramatic irony is commonly used in literary works including short stories and novels; in this type of irony, the audience or reader has key information one or more characters involved ignore. For example, the main character does not know his best friend is his enemy, but the reader knows this.
Option A " Two characters wearing masks at a costume party meet..." is an example of dramatic irony because in this case, the reader knows the two characters are good friends but the characters involve do not know this, and believe the other is just a stranger.