No, the answer is C. If it was A and the air cools, then why are deserts hot? The answer is C because as air rises it heats up and lose a its moisture through evaporation, leaving hot dry air for the deserts. This is called the rain shadow effect, where one side of the mountain is moist and cool and the other side is a desert.
The answer is, b. other substances
The resistance to being scratched is a mineral’s hardness.
This is the basis of the Mohs Hardness Scale.