Which One of the Following Statements Is Not a Postulate

Which one of the following statements is not a postulate of the kinetic molecular theory?

A) The size of a molecule is negligible.
B) Gas molecules move constantly and randomly throughout the space they occupy.
C) The average kinetic energy of a gas molecule is directly proportional to the absolute temperature of the gas.
D) Collisions of gas molecules with each other and with the walls of the container are elastic.
E) Gas molecules attract and repel each other.