Why are the D.C. motors preferred for traction applications ?

Q. Why are the D.C. motors preferred for traction applications ?

A.            Torque and speed are inversely proportional to armature current

B.            Torque is proportional to armature current

C.            Torque is proportional to square root of armature current

D.            The speed is inversely proportional to the torque and the torque is proportional to square of armature current

Answer: The speed is inversely proportional to the torque and the torque is proportional to square of armature current