The correct answer is A. Series motor.
A series motor is a type of DC motor that has the field winding and the armature winding in series with each other. This means that the current flowing through the field winding is the same as the current flowing through the armature winding. This results in a high starting torque, which makes series motors ideal for applications that require a lot of starting torque, such as cranes and hoists.
However, series motors also have a number of disadvantages. One disadvantage is that they have a poor speed regulation. This means that the speed of the motor will vary significantly with changes in load. Another disadvantage is that they are not very efficient. This is because the field winding is always energized, even when the motor is not under load.
A flywheel is a heavy wheel that is attached to the motor shaft. The flywheel helps to smooth out the torque fluctuations of the motor. This is important in applications where the motor is subject to intermittent light and heavy loads.
When the motor is under light load, the flywheel will continue to rotate even though the motor is not producing much torque. This helps to keep the load from stalling. When the motor is under heavy load, the flywheel will help to keep the motor from slowing down too much. This is important in applications where the motor needs to maintain a constant speed, such as in conveyor belts and machine tools.
In conclusion, a series motor is the most suitable type of DC motor to use with a flywheel for intermittent light and heavy loads. This is because series motors have a high starting torque and can maintain a constant speed even under varying loads.