Final answer:
The stopping distance when driving a car at a specific speed cannot be accurately determined by the options provided as they do not include factors like deceleration and reaction time which are critical for calculating the actual stopping distance.
Step-by-step explanation:
The distance d in feet it takes to come to a complete stop when driving a car at r miles per hour can be found using a specific formula which is typically a function of the square of the speed, the deceleration rate, and the driver's reaction time. While the exact formula can vary based on driving conditions, for instance, dry vs. wet pavement, a common physics-based relationship applies. However, the four options provided in the question do not directly reflect a known stopping distance equation, which usually includes factors like deceleration and reaction time.
An accurate way to determine stopping distance takes into account the initial speed of the car, the deceleration rate due to braking, and the driver's reaction time. For example, if a car is traveling at 30.0 m/s and can decelerate at 7.00 m/s2 on dry concrete, the stopping distance can be calculated using the formula d = v2 / (2a), where v is the initial velocity and a is the deceleration.