In approach areas of runways equipped with instrumental landing facilities any object within 4.5 km distance from runway end shall be considered as an obstruction if its height is more than A. 20 m B. 30 m C. 45 m D. 51 m

The correct answer is: C. 45 m

According to the International Civil Aviation Organization (ICAO), any object within 4.5 km distance from runway end shall be considered as an obstruction if its height is more than 45 m. This is to ensure that aircraft have a safe approach to the runway.

Option A is incorrect because it is the height of an obstruction that is considered as an obstruction, not the distance from the runway end.

Option B is incorrect because it is the height of an obstruction that is considered as an obstruction, not the distance from the runway end.

Option D is incorrect because it is the height of an obstruction that is considered as an obstruction, not the distance from the runway end.