What do you do if visibility is drastically reduced by fog?

Your selected combination is correct because, according to German traffic regulations, it is crucial to adapt your speed according to visibility conditions in fog, which ensures you can react appropriately to any potential hazards. Additionally, increasing the distance from the vehicle in front is necessary as it allows for a longer reaction time. Maintaining this safe distance is essential in limited visibility situations to avoid collisions. Driving closely to the vehicle ahead to rely on its rear lights is unsafe and not advised, as it significantly reduces your ability to respond to sudden stops or emergencies. Overall, the selected options emphasize safety and adherence to traffic rules in adverse conditions.