Answer
The answer is a only a). the brakes. The brakes cause a negative acceleration, causing the vehicle to stop. The string is not acceleration because only the direction is changing, the magnitude of the velocity is still the same. The gear shift just changes what mode the car is set to, as long as the foot is still on the pedal, the car will not accelerate. So the answer is only a). the brakes.
Work Step by Step
The answer is a only a). the brakes. The brakes cause a negative acceleration, causing the vehicle to stop. The string is not acceleration because only the direction is changing, the magnitude of the velocity is still the same. The gear shift just changes what mode the car is set to, as long as the foot is still on the pedal, the car will not accelerate. So the answer is only a). the brakes.