When is it allowed to use the horn?

1. Correct answer: Only to prevent imminent danger that cannot be prevented in any other way.
2. Only in an urban road, to prevent danger.
3. In every type of road, only for public vehicles, to prevent danger.
4. Only in a non-urban road, to prevent danger.

WhyThe horn is only for preventing an imminent danger that cannot be prevented any other way. On any road and for any vehicle.