The correct option is C North pole of a magnet is kept at a small distance from north pole of another magnet.
Magnetic force acts between two magnetic objects, when they are in contact as well as when they are not in contact with each other.
Since iron rod is a magnetic material, magnetic force acts between the iron rod and the magnet.
Magnetic force also acts between two poles of a magnet (Like poles repel and unlike poles attract).
Since wood is a non-magnetic material, magnetic force do not act between a piece of wood and a magnet.