The picture shows a basic diagram of an electric motor.

At top left a piece of magnet labeled N and at top right a piece labeled S. Between these a square coil of wire X sits attached to a metal rod, which runs between the 2 pieces of magnet. 2 semicircular pieces Z of metal surround the rod at its opposite end from the pieces of magnet. Wires connect to each semicircular piece at terminals Y to one pole of a battery. Blue arrows superimposed on the end of the coil away from the magnets point toward S and away from N.
Which labels best complete the diagram?

A - X: Brush
Y: Armature
Z: Commutator

B - X: Commutator
Y: Brush
Z: Armature

C - X: Armature
Y: Commutator
Z: Brush

D - X: Armature
Y: Brush
Z: Commutator