Doubt from Electro magnetic induction


I am getting a,b,c don't know about d

Is answer ABCD
Options ABC correspond to same case.
Angle between 2 adjacent points of collision is 120 degree about centre.
In option D angle between 2 adjeacent points of collision is 60degrees about centre.

Yes ans is ABCD. But I could not imagine the motion of particle inside cylinder, can you pls draw the diagram