What does a circular sign with a red border containing a black arrow pointing up and a red arrow pointing down signify ('Prvenstvo prolaza za vozila iz suprotnog smjera')?

1. Priority for oncoming vehicles; you must give way to oncoming traffic in narrow road sections (Prvenstvo prolaza za vozila iz suprotnog smjera)
2. You have priority over oncoming vehicles in narrow road sections
3. Two-way traffic ahead on a previously one-way street
4. Overtaking is permitted in both directions