Read the passage below and answer the question given below <br><br>
The blue colour of the sky is due to the scattering of the sunlight by the molecules of the atmosphere. The molecules of air, such as $N_2$ and $O_2$ have sizes smaller than the wavelength of visible light. As sunlight passes through the atmosphere these molecules absorb some amount of sunlight and re-emit it. They scatter blue light of shorter wavelength more strongly than red light of stronger wavelength. When we look at the sky scattered light enters our eyes and this light contains blue light in large proportion. That is why the sky appears blue. <br><br>
QUESTION : The colour of the sky in the absence of the atmosphere is
