Pick up the correct statement from the following :

Question:Pick up the correct statement from the following :

1.If two equal and perfectly elastic smooth spheres impinge directly, they interchange their velocities.

2.If a sphere impinges directly on an equal sphere which is at rest, then a fraction (1 - e2) the original kinetic energy is lost by the impact.

3. If a smooth sphere impinges on another sphere, which is at rest, the latter will move along the line of centres.

4.All the above.

Answer:4