In an elastic collision,
(a) Total momentum is conserved, i.e., total final momentum is equal to the total initial momentum.
(b) Total mechanical energy is conserved, i.e., toted final energy is equal to the total initial energy.
© Total kinetic energy is conserved, i.e., total final kinetic energy is equal to the total initial kinetic energy.
(d) Total forces are of conservative nature, i.e., work done do not depend upon the actual paths.