When vectoring an IFR flight over high terrain, the controller must keep the aircraft at or above a minimum vectoring altitude built on the ICAO minimum flight altitude criteria. Over mountainous areas, what clearance does that criterion require, and over what area is the highest obstacle assessed?

1. 1,000 ft (300 m) above the highest obstacle within 8 km of the estimated position of the aircraft
2. 1,500 ft (450 m) above the highest obstacle within 8 km of the estimated position of the aircraft
3. 2,000 ft (600 m) above the highest obstacle within 8 km of the estimated position of the aircraft
4. 3,000 ft (900 m) above the highest obstacle within 18.5 km (10 NM) of the estimated position of the aircraft