In which of these dangerous situations does a vehicle equipped with the so-called ASR, i.e. Acceleration slip regulation system designed to prevent loss of traction of driven road wheels perform well?

The question is about the ASR system, which prevents the driven wheels from spinning when moving off. It works best when moving off sharply on a slippery surface - answer C. Going downhill (A) is a job for the brakes, and simply driving uphill (B) does not make the wheels spin if the surface is dry.

When on ice, snow or wet leaves you press the accelerator too hard, the driven wheel loses grip and spins on the spot; in a front-wheel-drive car the front starts to slide to the side, in a rear-wheel-drive car the rear may swing out. ASR detects the difference in rotation between the wheels and reacts immediately: it brakes the spinning wheel and limits the engine torque, so that the tyre rolls on the surface again and the car moves off straight. The driver can help the system: in a car with a manual gearbox, move off in second gear, press the accelerator smoothly and do not turn the wheels sharply when moving off. Switching off ASR makes sense only in exceptional cases, for example when you need to get out of deep snow, where wheel spin is actually needed.