Solution

(b) zero

Magnetic material consists of many tiny magnets called magnetic domains. These tiny magnets (domains) have their own north and south poles. There are approximately equal numbers of magnetic domains at the left and right side of the magnet with opposite polarity. This creates a narrow magnetic neutral zone. No magnetic force lines come out or terminate at the center of the bar magnet. All magnetic force lines remain within the bar, so the center remains at zero magnetism.