Concept:An inelastic collision conserves linear momentum but does not conserve kinetic energy.
Explanation:In any collision, total energy is always conserved, but kinetic energy may change.
In an inelastic collision, some kinetic energy is converted to heat, sound, or deformation.
Therefore, kinetic energy decreases, so statement II is correct.
Linear momentum is always conserved in collisions when no external force acts, so statement IV is correct.
Statements I and III are incorrect because kinetic energy is not conserved or increased.
Answer:II and IV only.
Correct option: B.