Six identical balls are lined in a straight groove made on a horizontal frictionless surface as shown. Two similar balls each moving with a velocity v collide elastically with the row of 6 balls from left. What will happen

All the six balls in the row will roll out with speed v/6 each and the two colliding balls will come to rest

The colliding balls will come to rest and no ball rolls out from right

One ball from the right rolls out with a speed 2v and the remaining balls will remain at rest

Two balls from the right roll out with speed v each and the remaining balls will remain stationary