Final answer:
The sound of the old man's heart in 'The Tell-Tale Heart' symbolizes the guilt of the narrator.
Step-by-step explanation:
The sound of the old man's heart most closely symbolizes the guilt of the narrator. In Edgar Allan Poe's short story 'The Tell-Tale Heart,' the narrator is plagued by the overwhelming guilt of killing the old man. The sound of the heart represents the narrator's conscience and his inability to escape his guilt.
Learn more about Symbolism in 'The Tell-Tale Heart'