Compared to Earth's Atmosphere, the Atmosphere of Mars Has Surface

Compared to Earth's atmosphere, the atmosphere of Mars has surface pressures that are ___________.

A) 0.1 times those on Earth; major gases are water vapor and carbon dioxide
B) 1.5 times those on Earth; main gases are methane and nitrogen
C) one- half those on Earth; main gases are methane and nitrogen
D) 3 times those on Earth; major gases are water vapor and carbon dioxide