Within which distance from a tunnel is it prohibited to overtake?

1. Correct answer: Fifty meters before the entry to the tunnel and up to fifty meters after the exit from the tunnel.
2. There is no overtaking restriction around a tunnel.
3. 100 meters before the entry to the tunnel and up to 100 meters after the exit from the tunnel.
4. From the entry until the exit of the tunnel.

WhyOvertaking is forbidden from 50 meters before the tunnel entrance to 50 meters after its exit. And inside it too, of course.