A radar has a power of `1kW` and is operating at a frequency of `10 GHz`. It is located on a mountain top of height `500m`. The maximum distance upto which it can detect object located on the surface of the earth (Radius of earth `6.4xx10^(6)m`) is

Options

A. 16 km
B. 40 km
C. 64 km
D. 80 km

Answer

D