Correct option is B
In tapped field control, the field winding is divided into sections, and the number of turns in the field circuit controls the speed. When all the field turns are present, the flux is maximized, and the speed is minimized.
In a tapped field control for a DC series motor, the speed is controlled by varying the number of turns in the field winding that are active.
By using a switch to short-circuit parts of the field winding, the flux is reduced, and consequently, the motor speed increases.
When all the field turns are in the circuit, the motor runs at its lowest speed, and by progressively short-circuiting turns, the speed can be increased in steps.
