When visibility of the road is less than 100 m in at least one direction
In all the above cases✓Richtige Antwort
Erklärung
Every situation listed removes the sight distance or clear space needed for a safe U-turn: pedestrian crossings, tunnels, bridges and related structures, rail crossings, and locations with less than 100 m visibility. Treating any one of them as an exception would contradict the same prohibition.