Correct option is D
In a
DC shunt motor, if the connection of the field winding is reversed, the direction of the magnetic field will change.
Since the direction of rotation of a DC motor is determined by both the direction of the armature current and the magnetic field, reversing the field winding will result in the motor running in the
opposite direction.
Thus, changing the connection of the field winding changes the polarity of the magnetic field, causing the motor to reverse its rotation.
