What is the benefit of using adaptive cruise control (ACC) on motorways?

You answered correctly. Adaptive cruise control (ACC) helps the driver by automatically maintaining a set speed while also adjusting the speed to keep a safe distance from the vehicle ahead. This reduces the likelihood of rear-end collisions and assists the driver in keeping the chosen distance more consistently, especially on busy motorways. However, ACC does not guarantee that the safety distance can never be undercut—for example, if another vehicle suddenly moves into your lane too closely. That’s why only the first two answers are correct. Knowing this will help you understand how ACC supports but does not replace your own attention on the road.