The sun delivers $10^{4} \mathrm{Wm}^{-2}$ of electromagnetic flux to the earth's surface. The total power that in incident on a roof of dimensions $10 \mathrm{~m}^{2}$ will be
(a) $10^{4} \mathrm{~W}$
(b) $10^{5} \mathrm{~W}$
(c) $10^{6} \mathrm{w}$
(d) $10^{7} \mathrm{~W}$