The windscreen washer does not work. What can be the reason for this?

The selected combination of answers is correct because each option represents a potential reason for non-functioning windscreen washers. According to German traffic regulations, maintaining visibility is crucial for safe driving, and the windscreen washer system is vital for keeping the windscreen clear of dirt and debris.

1. No water in the reservoir means that the system cannot function at all, leading to impaired visibility.
2. A defective fuse can stop the electrical system from operating, which is necessary for the pump to work.
3. Blocked jets prevent the washer fluid from reaching the windscreen, rendering the system ineffective even if other components are functioning.

All three aspects must be checked to ensure the windscreen washer is operational and that the driver can maintain proper visibility, which is essential for safe driving. Ignoring any of these could lead to potential visibility hazards, which is against traffic safety regulations in Germany.