Final answer:
Man-made permanent magnets retain their magnetism more effectively than natural magnets due to their material composition and the manufacturing process designed to maintain magnetism over time.
Step-by-step explanation:
The question compares the effectiveness of magnetism retention between man-made permanent magnets and natural magnets. Man-made permanent magnets are designed and manufactured to hold their magnetic properties more effectively than natural magnets. This capability is due to the material composition and manufacturing process which allows them to retain their magnetic behavior for extended periods, even when exposed to demagnetizing forces.
Based on this understanding, man-made permanent magnets retain their magnetism more effectively (Option B) than natural magnets. Today's technology enables the creation of permanent magnets with significant magnetic field strengths, such as 0.500 T, which demonstrates the effectiveness of man-made permanent magnet technology.