Fill in the blank (_) in the following sentence from the following choices.
Sentence: I had to change the tire on the car but not the one on the truck because the one on the _ was flat.

Choice 1: I had to change the tire on the car but not the one on the truck because the one on the car was flat.
Choice 2: I had to change the tire on the car but not the one on the truck because the one on the truck was flat.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
2.