The correct answer is: A. Split motor.
A split-phase motor is a type of single-phase induction motor that has two windings on the stator: a main winding and a starting winding. The main winding is connected directly to the power supply, while the starting winding is connected to the power supply through a capacitor. When the motor is turned on, the current in the starting winding creates a magnetic field that is out of phase with the magnetic field of the main winding. This creates a torque that starts the motor rotating. Once the motor is up to speed, the starting winding is disconnected from the power supply and the motor continues to run on the main winding.
A shaded-pole motor is a type of single-phase induction motor that has a single winding on the stator. The winding is divided into two sections by a copper band called a shading ring. The shading ring creates a magnetic field that is out of phase with the magnetic field of the main winding. This creates a torque that starts the motor rotating. Once the motor is up to speed, the shading ring has no effect on the motor’s operation.
A reluctance motor is a type of single-phase induction motor that has a stator with a non-uniform magnetic reluctance. This means that the magnetic field lines prefer to flow through some parts of the stator than others. When the motor is turned on, the magnetic field lines flow through the parts of the stator with the lowest reluctance. This creates a torque that starts the motor rotating. Once the motor is up to speed, the magnetic field lines flow through all parts of the stator equally and the motor continues to run without any additional torque.
Therefore, the only motor that is inherently self-starting is the split-phase motor.