Fill in the blank (_) in the following sentence from the following choices.
Sentence: James found out some stain on his teeth even after using the brush. The _ is weak.

Choice 1: James found out some stain on his teeth even after using the brush. The brush is weak.
Choice 2: James found out some stain on his teeth even after using the brush. The stain is weak.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
2. The stain is weak.