Fill in the blank (_) in the following sentence from the following choices.
Sentence: Robert killed his fish but Joseph did not since _ forgot to feed his Koi everyday.

Choice 1: Robert killed his fish but Joseph did not since Robert forgot to feed his Koi everyday.
Choice 2: Robert killed his fish but Joseph did not since Joseph forgot to feed his Koi everyday.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
2.