Fill in the blank (_) in the following sentence from the following choices.
Sentence: William yelled at Jason when _ found out how much they charged to the credit card.

Choice 1: William yelled at Jason when William found out how much they charged to the credit card.
Choice 2: William yelled at Jason when Jason found out how much they charged to the credit card.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
2.