Fill in the blank (_) in the following sentence from the following choices.
Sentence: Mary preferred to eat the milkshake over the ice cream because the _ was too old.

Choice 1: Mary preferred to eat the milkshake over the ice cream because the milkshake was too old.
Choice 2: Mary preferred to eat the milkshake over the ice cream because the ice cream was too old.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
2
2.