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 distance of the seismic recording station from the earthquake epicenter is determined from the time difference between the first arrival of the P-wave and the S-wave. This is known as the S-P interval.