ratio of the temperatures of surfaces for a given emissivity

Question

The total emissive power of a surface is 500 W/m² at a temperature T₁ and 1200 W/m² at a temperature T₂, where the temperature are in Kelvin. Assuming the emissivity of the surface to be constant, the ratio of the temperatures $\frac{T_{1}}{T_{2}}$   is                                                                 

      (a) 0.308                                                             (b) 0.416

      (c) 0.803                                                             (d) 0.874