Answer:
D The magnetic field reverses direction.
Step-by-step explanation:
An electric motor works based on the principle of electromagnetic induction. It is the interaction of electric current and the magnetic field that makes a motor function.
An electric motor is a machine that will convert the electric energy to mechanical energy. In this a commutator is used to change the direction of current.
When the direction of flow of current is made to change, the magnetic field also reverses the direction.
There are different types of motors like AC motor,DC motor, Induction motor etc.