The Sun having radius R and surface temperature T emits radiation as a perfect emitter. The distance of the earth from the sun is r and the radius of the earth is $$R_e$$. The total radiant power incident on the earth is

A

$$\frac{ R^2 R_e^2\sigma T^4}{4\pi r^2}$$

B

$$\frac{R^2 R_e^2\sigma T^4}{r^2}$$

C

$$\frac{4\pi R^2 R_e^2\sigma T^4}{r^2}$$

D

$$\frac{\pi R^2 R_e^2\sigma T^4}{r^2}$$