Final answer:
The stopping distance of a car depends on several factors and cannot be determined without additional information.
Step-by-step explanation:
The stopping distance of a car depends on various factors, such as the speed of the car, the coefficient of friction between the tires and the road, and the driver's reaction time. To calculate the stopping distance at 50 mph, we need additional information like the reaction time and the coefficient of friction. Therefore, none of the provided answer choices (a. 135 ft, b. 409 ft, c. 302 ft, d. none of the above) can be determined without the necessary details.