What applies here?

Your choice (answer 1: “The crossroads may be crossed”) is correct because a police officer’s hand signals override traffic lights, signs, and the usual right-of-way rules.

Rule of thumb for police signals: you must interpret what the officer is “showing” with their body. If you see the officer’s side (their right or left side facing you), traffic from your direction is allowed to go straight on and also allowed to turn. Only if you face the officer’s front or back do you have to stop and wait.

In this situation the officer is standing sideways to you, so you may enter and cross the intersection. You do not have to wait for “further signals” as long as the current signal permits your direction, and turning is not generally prohibited here unless the officer gives a stop signal or there is an explicit sign banning the turn.