(a, b, c, d)

Initially the current induced in the hollow conductor is zero because the magnet was at rest. When the magnet falls, due to the variation of magnetic flux, induced current develop in the hollow conductor so as to resist the cause of increment of flux; that means the velocity of the magnet is resisted. In the other word we can say that the magnet is retarded before entering into the hollow conducting cylinder. Consequently its acceleration will be less than g because magnetic force opposes the gravitational force, acting on the magnet. If the cylinder is too long, the magnetic force opposes the gravitational force, on the magnet so as to yield zero acceleration after a long time, to attain a terminal velocity.