Fill in the blank (_) in the following sentence from the following choices.
Sentence: Lawrence wanted to teach calculus while Derrick wanted to teach comic strips because _ was a serious teacher.

Choice 1: Lawrence wanted to teach calculus while Derrick wanted to teach comic strips because Lawrence was a serious teacher.
Choice 2: Lawrence wanted to teach calculus while Derrick wanted to teach comic strips because Derrick was a serious teacher.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
1.