The correct answer is: Series motor.
A series motor has poor starting torque because the field winding is connected in series with the armature winding. This means that the current through the field winding is the same as the current through the armature winding. When the motor is first started, the armature current is high, which causes a high magnetic field. This high magnetic field creates a strong torque that causes the motor to start. However, as the motor speeds up, the armature current decreases. This decrease in armature current causes a decrease in the magnetic field, which causes a decrease in the torque. This decrease in torque can make it difficult for the motor to start up.
A shunt motor has good starting torque because the field winding is connected in parallel with the armature winding. This means that the current through the field winding is independent of the current through the armature winding. When the motor is first started, the armature current is high, but the field current is low. This low field current creates a weak magnetic field, which creates a small torque that causes the motor to start. However, as the motor speeds up, the armature current decreases, but the field current remains constant. This constant field current creates a strong magnetic field, which creates a large torque that helps the motor to maintain its speed.
A differentially compounded motor has poor starting torque because the field windings are connected in series with each other, but in opposite directions. This means that the current through the field windings is in opposite directions. This opposite current creates a magnetic field that is weaker than the magnetic field created by a single field winding. This weaker magnetic field creates a smaller torque that makes it difficult for the motor to start.
A cumulatively compounded motor has good starting torque because the field windings are connected in series with each other, but in the same direction. This means that the current through the field windings is in the same direction. This same current creates a magnetic field that is stronger than the magnetic field created by a single field winding. This stronger magnetic field creates a larger torque that helps the motor to start.