Two Protons Are Fired Toward Each Other in a Particle

Two protons are fired toward each other in a particle accelerator,with only the electrostatic force being exerted.Which of the following statements must be true about them as they move closer together? (There could be more than one correct choice.)

A) The electric potential energy of the system of the two protons keeps increasing.
B) Their kinetic energy keeps increasing.
C) The electric potential energy of the system of the two protons keeps decreasing.
D) Their kinetic energy keeps decreasing.
E) Their acceleration keeps decreasing.