What must you be prepared for?

Your answers 1, 2 and 3 are all correct because this is a typical “narrow street with parked cars” risk situation. In German traffic rules this falls under the general duty of care (StVO §1): you must drive in a way that you can react to foreseeable hazards.

Answer 1 (persons crossing): Pedestrians can suddenly step into the roadway from between parked cars, often without being visible early. This is especially common near entrances, shops, bus stops, or when people walk to/from parked cars. You must be ready to brake immediately.

Answer 2 (visual obstructions): Parked cars, delivery vans, and building edges block your view. That means you may not see oncoming vehicles, cyclists, or pedestrians until very late. Rule of thumb: if your view is restricted, reduce speed and increase lateral clearance so you can stop within the visible distance.

Answer 3 (vehicle doors opening): People can open doors into your path without checking (the “dooring” risk). German practice is to keep enough side distance to parked cars and to be prepared to brake, because an opening door is considered a typical, predictable danger in such streets.

For similar questions: whenever you see parked cars lining both sides, assume “hidden pedestrians + blocked sight lines + doors opening,” and adjust speed and position accordingly.