dependant clause, cause we don't know who "who" is and the first sentance tells us this. If the sentence was on it's own without the context, we'd have no idea who "who" is.
Assuming that Jordan here is a person of 'The great Gatsby.' Jordan Baker is insulted because Nick called her loose, among other things. The way she responds him is by ignoring (in the book), but in the movie, storms out.
Answer:
He hears the old man's heartbeat, and it symbolizes his guilt.
Explanation: