The correct answer is: C. 4 m
The height of the pilot’s eye above the runway surface is assumed to be 4 m. This is because the pilot needs to be able to see the runway clearly in order to land the aircraft safely. If the pilot’s eye were any lower, they would not be able to see the runway and would be at risk of landing the aircraft in the wrong place.
Option A is incorrect because it is too low. The pilot needs to be able to see the runway clearly in order to land the aircraft safely. If the pilot’s eye were any lower, they would not be able to see the runway and would be at risk of landing the aircraft in the wrong place.
Option B is incorrect because it is too high. The pilot does not need to be able to see the runway from that high up. In fact, it would be more difficult for them to land the aircraft if they were looking down from that high up.
Option D is incorrect because it is not a realistic height. The pilot’s eye is not likely to be 5 m above the runway surface.