The sun having surface temp. Ts radiates like black body. the radius of sun is Rs and earth is at a distance R from the surface of sun earth absorbs radiation falling on its surface from sun only and is at constant temp. T . If radiation falling on earth's surface are almost parallel and earth also radiates like black body,then

A. T=TsRs/2R  B. T=Ts  C. T=Ts/2 Rs/R  D.  T=Ts Rs/R