Fill in the blank (_) in the following sentence from the following choices.
Sentence: He couldn't fit the soda bottle on the refrigerator shelf because the _ was too short.

Choice 1: He couldn't fit the soda bottle on the refrigerator shelf because the shelf was too short.
Choice 2: He couldn't fit the soda bottle on the refrigerator shelf because the bottle was too short.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
2.