A camera equipped with a 152 mm focal length lens, is used to take a vertical photograph from a flying height of 2780 m. above mean sea level. If the terrain is flat with an elevation of 500 m, the scale of the photograph will be
1
1 ∶ 15,000
2
1 ∶ 24,500
3
1 ∶ 22,000
4
1 ∶ 20,000