Multiple choice please help physics?

Physics help please - multiple choice: In an elastic collision involving....?

• In an elastic collision involving two interacting objects, the final kinetic energy of the system: a) can be equal to the kinetic energy of the system. b) is always less than or equal to the initial kinetic energy of the system. c)is always greater than or equal to the initial kinetic energy of the system d) is always less than the initial kinetic energy of the system e) can be greater than the initial kinetic energy of the system please explain your answer, thanks a bunch

• Answer:

  it's (b) because in an elastic collison, momentum is conserved, not necessarily KE though, in a perfectly elastic collision, then both are conserved. it can' any f the others cuz energy cannot be created therefore anything that says 'greater' is wrong. Suggestion : post all your Q's at one time, much easier if u have a lot more ;)