The correct answer is: A. Lie under South Pole.
The brushes on a DC generator are in contact with the commutator, which is a series of metal rings that are insulated from each other. The commutator is connected to the rotor, which is the rotating part of the generator. As the rotor turns, the commutator causes the brushes to make contact with different conductors, which creates an electric current.
The conductors that are in contact with the brushes are located under the south pole of the magnet. This is because the magnetic field lines from the south pole are directed towards the brushes. When the brushes come into contact with these conductors, they pick up electrons from the conductors. These electrons are then carried away by the current that is generated by the generator.
The other options are incorrect because they do not describe the location of the conductors that are in contact with the brushes. Option B is incorrect because the conductors that are in contact with the brushes are not located under the north pole. Option C is incorrect because the conductors that are in contact with the brushes are not located under the interpolar region. Option D is incorrect because the conductors that are in contact with the brushes are not located farthest from the poles.