A traffic jam is building up here. What is the correct procedure?

Your choices 1 and 2 are correct.

In Germany, when traffic suddenly slows down and a jam is forming, you should warn drivers behind you early. That’s why switching on the hazard warning lights (answer 1) is correct: it alerts following traffic that there is an unexpected queue ahead, which helps prevent rear-end collisions.

At the same time, you must start forming an emergency corridor (“Rettungsgasse”) as soon as traffic becomes slow or stops on motorways and similar multi-lane roads. With two lanes in one direction, the rule is: vehicles in the left lane move as far left as possible, and vehicles in the right lane move as far right as possible. That creates a free passage in between for emergency services. So moving as far right as possible (answer 2) is correct here, because it helps create the corridor on the left side of your lane.

Moving left to create a corridor on the right (answer 3) is wrong in this situation: the emergency corridor is not created on the far right; it is created between the leftmost lane and the lane next to it (and similarly between lanes on roads with more lanes).