In which situations are you not allowed to enter a junction even though the traffic light is green?

You answered correctly by selecting options 1 and 2. According to German traffic regulations, even if the traffic light is green, you must not enter a junction if doing so would mean stopping in the middle because of backed-up traffic (option 1) or if instructed to stop by a police officer (option 2).

These rules are in place to ensure smooth traffic flow and safety, preventing gridlock in traffic situations where vehicles should not obstruct the junction. However, option 3 is not correct in this context, as a sign like "Stop. Give way" indicates a requirement to yield to other traffic, but it doesn't apply when the traffic light is green. Understanding these nuances can help you navigate intersections safely and effectively while complying with traffic laws.