Magnetic repulsion increases apparent weight

Steps:

• Balance reading measures downward force on X (apparent weight).
• Increased reading when Y nears X indicates added downward force on X.
• Y above X means this force is repulsive, directed downward on X.
• Repulsion requires both objects to be magnets with like poles facing.

Why B is correct:

• Two magnets can repel via like poles (magnetic force law: like poles repel), adding downward force on X and raising balance reading.

Why the others are wrong:

• A: Plain iron lacks magnetism for repulsion; no force change.
• C: Magnet X attracts iron Y, pulling X upward and decreasing reading.
• D: Magnet Y attracts iron X upward, decreasing reading.

Final answer: B