Fill in the blank (_) in the following sentence from the following choices.
Sentence: The brush james bought could not get the stain off his teeth because the _ is too tough.

Choice 1: The brush james bought could not get the stain off his teeth because the brush is too tough.
Choice 2: The brush james bought could not get the stain off his teeth because the stain is too tough.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
2
2.