When an aircraft's altimeter subscale is set to the current aerodrome QNH, what will the altimeter indicate while the aircraft is parked on the runway?

1. Zero feet (0 ft)
2. The pressure altitude corresponding to standard 1013.25 hPa
3. The official elevation of the aerodrome above Mean Sea Level (AMSL)
4. The vertical distance between the aerodrome and the cloud base