What should you do now?

You selected answers 1 and 2, which are correct. When you are following another vehicle on a multi-lane road, you must always maintain a safe distance and be prepared to reduce your speed, especially when approaching curves or if you cannot see far ahead. Passing quickly (answer 3) would be risky in this situation because visibility may be limited by the curve, and you must not put yourself or others in danger. The rule of thumb is: slow down and stay behind the vehicle ahead until it is clearly safe to overtake, and only do so when you have a good overview and conditions allow. This approach keeps everyone safe and follows German road safety regulations.