a. bluish because the gas is shining by reflected starlight and the blue starlight scatters more
b. bluish because the gas and dust in the nebula are reflecting light from hot stars
c. reddish because the gas is mostly hydrogen which is bright in the red hydrogen light
d. reddish because the gas is cool so by Wien's Law the light is mostly red
e. nearly white because the balance of the light results in a combination perceived by the eye as white