Hello! :)
C). Its atmosphere.
Why?
It contains the oxygen that we breath as well as other important gases such as nitrogen, carbon dioxide, water vapor, and ozone. It protects us from the Sun's harmful rays, burns and destroys meteors that are headed toward Earth, and it keeps our planet from having extreme temperature changes.The Earth's atmosphere is protecting us from meteoroids in an amazing way. The Earth's atmosphere is good at shielding its inhabitants from space rocks hurtling towards the planet because of its strong air pressure, scientists have found.
Hope I answered in time.
Good luck!
~ Destiny ^_^