A particle moving with kinetic energy 3 J makes an elastic head-on collision with a stationary particle which has twice its mass. During the impact, (a) the minimum kinetic energy of the system is 1 J (b) the maximum elastic potential energy of the system is 2 J (c) momentum and total energy are conserved at every instant (d) the ratio of kinetic energy to potential energy of the system first decreases and then increases