The Temperature of a Gas Sample in a Rigid Container

Multiple Choice

The temperature of a gas sample in a rigid container is reduced. The pressure the gas exerts on the container walls decreases because

A) its molecules are in contact with the walls for briefer intervals.
B) its molecular masses decrease.
C) its molecules have lower average speeds and so strike the walls less often with less momentum.
D) its molecules lose less energy each time they strike the walls.