Repulsion Confirms Permanent Magnetism

Steps:

• Permanent magnets have north and south poles that attract opposites and repel likes.
• Unmagnetized ferromagnetic materials only attract to magnets via induction, without repulsion.
• Test with a known magnet: attraction alone could be induction in iron.
• Repulsion between like poles proves inherent magnetic domains, not temporary induction.

Why D is correct:

• Repulsion follows the law that like magnetic poles repel, confirming fixed north-south polarity in a permanent magnet.

Why the others are wrong:

• A: Compass needles (small magnets) align and attract to either pole but can also be drawn to induced magnetism in non-magnets.
• B: Attraction occurs with any ferromagnetic material, not proving permanent magnetism.
• C: Electrical conductivity is a metallic property unrelated to magnetic fields.

Final answer: D