In Which of the Following Statements Is the Gas Variable

In which of the following statements is the gas variable (in italics) correctly described?

A) Temperature is a measure of the space occupied by a gas.
B) Volume increases as the collisions of gas particles with the walls of the container increases.
C) Temperature is related to the average speed of gas particles.
D) The number of moles of a gas decreases as the volume of the gas increases.
E) When gas particles move faster, the pressure of the gas must increase.