How do you sound?

How do I make a single person listen to audio in a game?

For example: Player 1 and Player 2 are in a game together. They are both doing a quiz using GUIs (Not bricks). Player 1 gets the question correct, and ONLYhe hears a happy song. Player 2 gets the question wrong, and ONLY he hears a sad song. How do I make it so only one person can hear audio?

I am not going to be putting the audio in a brick, and putting a player right next to the brick.