The correct answer is: A. Shunt motor
A shunt motor is a type of DC motor that has a shunt field winding connected in parallel with the armature winding. This type of motor is used in applications where a constant speed is required, such as in conveyor belts and cranes.
A series motor is a type of DC motor that has a series field winding connected in series with the armature winding. This type of motor is used in applications where a high starting torque is required, such as in traction motors.
A differential compound motor is a type of DC motor that has a series field winding and a shunt field winding. The series field winding is connected in series with the armature winding, and the shunt field winding is connected in parallel with the armature winding. This type of motor is used in applications where a high starting torque and a constant speed are required.
A cumulative compound motor is a type of DC motor that has a series field winding and a shunt field winding. The series field winding is connected in series with the armature winding, and the shunt field winding is connected in parallel with the armature winding. The shunt field winding is stronger than the series field winding. This type of motor is used in applications where a high starting torque and a high speed are required.
In conclusion, the type of DC motor used for shears and punches is a shunt motor.