Four freshman partied too hard

Four freshman partied too hard during a music festival and unable to make it back for their final exam the next day

As they drove back to the college, they tried to think of a good excuse.
Finally, they agreed to the same story: a tire was blown in the middle of nowhere at mid night so they were stuck. They each sent the professor an email asking to retake the exam and gave the excuse
The understanding professor said it’s fine and ask them to take it the next day, but for fairness they would have to take a different exam.

The next day they came to the exam room, and as per usual procedure, each obtained a copy of the exam and sat in a corner.

The classroom was big and empty, the professor sat and watched them, so they were nervous.
Fortunately, the questions on the first page are fairly easy.
Even though these questions only worth 10/100 points, it calmed them down a bit.
So they quickly finished the first page at the same time and turned to the second page.
There was a single question on it:

(90/100) Which tire was blown?