In order to remind drivers to prevent traffic accidents, you can often see slogans such as "For safety, please keep a distance between cars!" posted on the rear windows of cars.

When a car is driving at high speed, it must maintain its original high-speed driving state due to inertia. If the speed is too fast, when the car encounters an emergency and brakes, the braking distance required by the car will become longer, which may easily cause traffic accidents. Therefore, "for safety, please keep a distance between cars" is to remind the driver behind not to drive too fast, and to prevent rear-end collisions caused by emergency braking. Therefore, AC is consistent with the meaning of the question.

So choose AC.