Two carts are placed together at rest. A spring-loaded piston attached to one cart is then released, causing the carts to move in opposite directions. What is conserved in this process?

1. Momentum but not kinetic energy (18/33) (55%)
2. Kinetic energy but not momentum (1/33) (3%)
3. Both momentum and kinetic energy (14/33) (42%)
4. Neither momentum nor kinetic energy (0/33) (0%)