Deserts Typically Occur in a Band at 20 Degrees North

Deserts typically occur in a band at 20 degrees north and south latitude because

A) descending air masses tend to be cool and dry.
B) trade winds have a little moisture.
C) moisture-laden air is heavier than dry air and is not carried to these latitudes.
D) ascending air tends to be moist.
E) these locations get the most intense solar radiation of any location on Earth.