Neptune and Uranus Both Appear Bluish in Sunlight Whereas Jupiter

Multiple Choice

Neptune and Uranus both appear bluish in sunlight whereas Jupiter and Saturn are multicolored. Why are Neptune and Uranus blue?

A) They contain methane ice in their atmosphere which causes the color.
B) They do not contain dust and debris in the atmosphere, like Saturn and Jupiter.
C) They contain ice crystals high in the atmosphere, and water ice is blue.
D) The effect is not real; it is just due to low light levels.