What should you be prepared here?

You answered correctly because both extending the braking distance and the possibility of reduced driving stability are important to consider in this situation.

This scene shows a road with loose material or soil on the right side, and the vehicle's speed is about 80 km/h. When driving near such surfaces, loose soil or gravel can reduce the friction between the tires and the road, which negatively affects driving stability and increases the risk of skidding. This makes it necessary to be prepared for reduced stability.

At the same time, the braking distance must be extended because traction is reduced on loose surfaces compared to clean tarmac. Braking too hard or too late can cause your vehicle to slide, making it harder to stop safely.

Therefore, in German traffic rules and safe driving practice, when you encounter such conditions, you should reduce speed, extend braking distance, and be cautious about handling to maintain stability. Reducing braking distance (option 3) would be incorrect as it could lead to dangerous situations.