The dramatic irony in the end is that the life of the protagonist's husband caused her death.
Explanation:
This question is about the short story "The Story of an Hour". At the beginning of the reading, we learned that the protagonist just received the news that her husband died. At that moment, we are led to believe, by the narration, that she is deeply sad, especially when the narration states that "She did not hear the story as many women have heard the same, with a paralyzed inability to accept its significance." However, we learned, throughout the story, that the character is very happy, because her husband's death means her freedom. She is so happy that she gets a big shock when she finds out that he is alive. This shock causes her to die shortly thereafter.
