The correct option is D Does it affect the direction in which a compass needle points?
A magnetic compass points north because all magnets have two poles, a north pole and a south pole, and the north pole of one magnet is attracted to the south pole of another magnet.
When this magnetic compass is brought near a magnetic substance, there is change in the direction of the needle based on the polarity of the magnetic substance closer to it. Whereas for a non magnetic substance it is not so.
Hence, the direction in which a compass needle points will distinguish between a magnetic material and a non-magnetic material.