The Majority of Gas Molecules Are near the Earth's Surface

Multiple Choice

The majority of gas molecules are near the Earth's surface. Why does this mean that the atmospheric pressure will be greater there?

A) There are more gas molecules in the overlying air to press on objects.
B) The gas molecules are moving faster there.
C) The gas molecules are bigger there.
D) The gas molecules are heavier there.
E) The gas molecules are smaller there.