The correct answer is: C. Cumulatively compounded.
A cumulatively compounded DC motor has both a series field winding and a shunt field winding. The series field winding is connected in series with the armature, while the shunt field winding is connected in parallel with the armature. The series field winding provides a high starting torque, while the shunt field winding provides a constant speed. When a flywheel is used with a cumulatively compounded DC motor, the flywheel helps to smooth out the torque fluctuations caused by the starting and stopping of the motor. This results in a more efficient motor that requires less peak demand.
A level compounded DC motor has only a shunt field winding. The shunt field winding is connected in parallel with the armature, which provides a constant speed. However, the level compounded DC motor does not have the high starting torque of the cumulatively compounded DC motor.
An under compounded DC motor has a series field winding that is weaker than the shunt field winding. This results in a motor that has a lower starting torque than the cumulatively compounded DC motor, but a higher starting speed.
A differentially compounded DC motor has a series field winding that is stronger than the shunt field winding. This results in a motor that has a higher starting torque than the cumulatively compounded DC motor, but a lower starting speed.