When is it obligatory to place a warning triangle?

1. Only when a malfunctioning vehicle is left unsupervised.
2. Only when a malfunctioning vehicle is left standing for more than 24 hours.
3. Correct answer: Whenever it is necessary to abandon a vehicle on the road.
4. Only when a malfunctioning vehicle is left standing on an urban road.

WhyA warning triangle is placed whenever a vehicle has to be abandoned on the road. Not only for long stops or in town.