State if each of

A. False

Explanation: In an elastic collision, the energy and momentum of the entire system is conserved and not of individual bodies.

B. False

Explanation: External forces can do work on the system and hence, they can change the total energy of the system.

C. False

Explanation: Work done in the motion of a body over a closed loop is zero only for conservative forces.

D. True

Explanation: In inelastic collisions, the final kinetic energy is always less than the initial kinetic energy because some of the energy is lost during the process in the form of sound, heat, etc.