Why does Mars have an overall reddish color when we see its surface from afar?
A. This is an optical illusion caused by the Earth's atmosphere scattering the colors of light differently
B. Mars is completely cloudy, and its clouds are made of red materials
C. The material of Mars' surface contains a lot of iron oxide, the same chemistry that makes rusting metals look reddish
D. the giant volcanoes on Mars are constantly spewing out reddish lava
E. The martians are constantly at war, and spilling a lot of red blood