Outside populated areas, intercity buses are allowed to travel at up to 90 km/h on all roads. So it does not matter where the 
Under the Rules, outside populated areas intercity buses and minibuses are allowed to travel on all roads at up to 90 km/h (clause 69). Since the picture shows a road outside a populated area, this limit applies. Separate limits for large vehicles help keep passengers safe on long roads.
Option 1. 60 km/h is the general limit in populated areas, while this road is outside a populated area.
Option 2. 70 km/h applies to other (non-intercity) buses on ordinary roads outside populated areas.
Option 3. 80 km/h is a wrong value: it is not the maximum speed set for any bus in this situation.