●In DC shunt motors, the armature and field winding are connected in parallel and so the currents through each are relatively independent.

●The current through the field winding can be controlled with a field rheostat (variable resistor), thus allowing a wide variation in the motor speed over a large range of load conditions.

●This type of motors are used for driving the tools where wide range of speed is required.

Hence, the correct option is (A).