【单选题】A car is going around a racetrack at constant speed. The curves around the track have different radii. In which turn is the magnitude of the car's acceleration the greatest?
A.
It is the greatest in the turn with the greatest radius.
B.
It is the greatest in the turn with the smallest radius.
C.
The acceleration is zero everywhere because of the constant speed.
D.
More information is needed to determine the answer.