Answer : Option B

Explanation :

The two main parts of a generator or motor can be described in either mechanical or electrical terms:

Mechanical:

Rotor: The rotating part of an electrical machine
Stator: The stationary part of an electrical machine

Electrical:

Armature: The power-producing component of an electrical machine. In a generator, alternator, or dynamo the armature windings generate the electric current. The armature can be on either the rotor or the stator.
Field: The magnetic field component of an electrical machine. The magnetic field of the dynamo or alternator can be provided by either electromagnets or permanent magnets mounted on either the rotor or the stator.