Provide your best answer for the following math problem. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The problem is: if a tire rotates at 400 revolutions per minute when the car is traveling 144 km / h , what is the circumference of the tire ?
6 meters
13.1 meters.