Fill in the blank (_) in the following sentence from the following choices.
Sentence: The hummingbird really annoyed Nelson, but it didn't bother Ryan at all, because _ was very sensitive to sound.

Choice 1: The hummingbird really annoyed Nelson, but it didn't bother Ryan at all, because Nelson was very sensitive to sound.
Choice 2: The hummingbird really annoyed Nelson, but it didn't bother Ryan at all, because Ryan was very sensitive to sound.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
2.