The correct answer is: B. improve power factor and provide better speed regulation.
The stator winding in a compensated repulsion motor is used to improve the power factor and provide better speed regulation. The stator winding creates a magnetic field that interacts with the rotor field to produce torque. The stator winding also helps to reduce the amount of armature reaction, which is a magnetic field that is created by the current flowing through the rotor winding. Armature reaction can cause the motor to run at a lower speed than it is designed to run. The stator winding helps to reduce armature reaction by creating a magnetic field that opposes the armature field. This helps to keep the motor running at a more constant speed.
The other options are incorrect. Option A is incorrect because the stator winding does not provide mechanical balance. Option C is incorrect because the stator winding does not prevent hunting in the motor. Option D is incorrect because the stator winding does not eliminate armature reaction.