Six steel balls of identical size are lined up along a straight frictionless groove. Two similar balls moving with speed v along the groove collide with this row on the extreme left end. Then

all the balls will start moving to the right will speed v/8

one ball from the right end will move on with speed 2v and all the remaining balls will be are rest

all the six balls originally at rest will move on with speed v/6 and the incident balls will come to rest

two balls from the extreme right end will move on with speed v and the remaining balls will be at rest