Fill in the blank (_) in the following sentence from the following choices.
Sentence: Sully used an exercise ball on the new hardwood floor, and it worked great because the _ was sturdy.

Choice 1: Sully used an exercise ball on the new hardwood floor, and it worked great because the floor was sturdy.
Choice 2: Sully used an exercise ball on the new hardwood floor, and it worked great because the ball was sturdy.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
2.