The correct answer is: C. Is independent of brush shift
A repulsion motor is a type of electric motor that uses the repulsion principle to produce torque. The direction of rotation of a repulsion motor is independent of the brush shift. This is because the torque produced by a repulsion motor is due to the interaction of the magnetic fields of the stator and rotor windings. The stator windings are arranged in a star configuration, while the rotor windings are arranged in a delta configuration. When current is applied to the stator windings, a magnetic field is produced. This magnetic field interacts with the magnetic field of the rotor windings, which are also energized, to produce torque. The direction of rotation of the motor is determined by the relative polarity of the stator and rotor magnetic fields. The brush shift does not affect the polarity of the stator or rotor magnetic fields, so it does not affect the direction of rotation of the motor.
Option A is incorrect because the direction of rotation of a repulsion motor is independent of the brush shift.
Option B is incorrect because the direction of rotation of a repulsion motor is not the same as that of the brush shift.
Option D is incorrect because the direction of rotation of a repulsion motor is not none.