The correct answer is D. all of the above.
The stator is the stationary part of a DC machine, while the rotor is the rotating part. The stator is made up of a frame, main poles, and interpoles. The frame provides support for the stator windings and the rotor. The main poles are the poles that produce the magnetic field that rotates the rotor. The interpoles are the poles that are located between the main poles and help to reduce eddy currents in the stator windings.
The stator windings are typically made of copper wire and are wound around the stator poles. The windings are connected to a DC power source, which creates a magnetic field in the stator. The magnetic field from the stator interacts with the magnetic field from the rotor, which causes the rotor to rotate.
The stator is an important part of a DC machine and plays a vital role in its operation.