Fill in the blank (_) in the following sentence from the following choices.
Sentence: Christopher dropped out of school instead of graduating alongside Kenneth, because _ was unable to cope with the academic stress.

Choice 1: Christopher dropped out of school instead of graduating alongside Kenneth, because Christopher was unable to cope with the academic stress.
Choice 2: Christopher dropped out of school instead of graduating alongside Kenneth, because Kenneth was unable to cope with the academic stress.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
1.