Does a driver's level of attention decrease when using a mobile phone?
A)Only if they do not use a hands-free system or if they write a text message.
B)No; talking on the phone does not affect the driver's attention.
C)Yes, even if they use a hands-free device.Correct
# Explanation
The use of the mobile phone decreases the driver's attention **even with hands-free systems**, because cognitive (mental) distraction is unavoidable when holding a conversation. Even if you don't use your hands, your mind is divided between driving and the call, reducing your ability to react to risk situations on the road.