Explain the term “service brakes”:

1. A A braking system that acts on all the wheels of a vehicle and allows slowing the vehicle down or stopping it in all road conditions.
2. B An auxiliary (parking/hand) brake system, designed to prevent accidents, which only acts on the wheels of the rear axle.
3. C A braking system that only slows the vehicle down during very steep descents, but is not used for stopping.
4. D A braking system that is working at times of danger only and brakes the vehicle until making a complete stop.