First Law of Thermodynamics: When an Ideal Gas Increases in Volume

First law of thermodynamics: When an ideal gas increases in volume at constant pressure, the average kinetic energy of the gas molecules

A) increases.
B) decreases.
C) does not change.
D) may either increase or decrease, depending on whether or not the process is carried out adiabatically.
E) may or may not change, but insufficient information is given to make such a determination.