Plz help meee it’s for 10 points

A magnetic field produced by a current can be turned on and off, it can have its direction reversed, and it can have its strength changed.

This rules out options A. and C.  

A magnetic field produced by a current can't speed up

by relation this rules out option B.

The answer is D, It can be turned on and off

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be