The graph shows how the speed of a car varies with time.

At time t=0.0 st = 0.0\text{ s}t=0.0 s, the driver sees a hazard in the road. At time t=0.6 st = 0.6\text{ s}t=0.6 s, the driver presses the brakes. At time t=2.6 st = 2.6\text{ s}t=2.6 s, the car stops.
What is the thinking distance of this car?
9.0 m9.0\text{ m}9.0 m
15.0 m15.0\text{ m}15.0 m
24.0 m24.0\text{ m}24.0 m
39.0 m39.0\text{ m}39.0 m