If the horizontal distance between the staff point and the point of observation is d, then the error due to curvature of earth is proportional to
A
$${\text{d}}$$
B
$$\frac{1}{{\text{d}}}$$
C
$${{\text{d}}^2}$$
D
$$\frac{1}{{{{\text{d}}^2}}}$$
Correct Answer: $${{\text{d}}^2}$$
