20. Which of the following describes fluid pressure against a flat surface?

(A) The pressure is equal to the change of momentum of the fluid molecules as they collide with the surface of the object divided by the time and the surface area.

(B) The pressure is equal to the change in kinetic energy of the fluid molecules as they collide with the surface of the object divided by the time and the surface area.

(C) The pressure is equal to the change in momentum of the fluid molecules as they collide with the surface of the object divided by the number of molecules and the surface area

(D) The pressure is equal to the temperature of the fluid molecules divided by the time and surface area.

(E) None of these.