How can you reduce the risk of driving onto a motorway against the stipulated direction?

The selected combination of options is correct because it emphasizes the importance of being vigilant about road signs and traffic routing when entering a motorway.

Traffic signs at slip roads indicate the correct direction of travel and help drivers avoid entering a motorway in the wrong direction, which is crucial for safety. Paying close attention to signage is essential, especially during changes in traffic routing, as this can help prevent confusion and misdirection.

On the other hand, relying solely on a navigation system during roadworks is risky, as these systems may not always account for temporary changes in route or traffic conditions. In German traffic law, drivers are expected to be aware of their surroundings and adhere to posted signs, which is why the combination of the first two options is necessary for minimizing the risk of driving the wrong way on a motorway.