Fill in the blank (_) in the following sentence from the following choices.
Sentence: Brett didn't believe Craig that essential oils worked, until _ proved that they were indeed effective.

Choice 1: Brett didn't believe Craig that essential oils worked, until Brett proved that they were indeed effective.
Choice 2: Brett didn't believe Craig that essential oils worked, until Craig proved that they were indeed effective.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
2
2.