Why does the Moon affect ocean tides?

Answer: Moon's gravity pulls the water

Moon's light heats the water — Wrong. Moonlight is just reflected sunlight and is very weak - it doesn't heat the ocean significantly. Temperature changes don't cause the regular twice-daily tides we observe. The tides are caused by gravitational forces, not thermal effects.

Moon's gravity pulls the water ✓ — Correct! The Moon's gravity pulls on Earth's oceans. The side of Earth facing the Moon experiences stronger pull, creating a bulge of water (high tide). Surprisingly, the opposite side also gets high tide because Earth itself is pulled more than that distant water, leaving it 'behind' in a bulge. As Earth rotates, locations pass through these bulges, experiencing two high tides daily (every 12.4 hours). The Sun also affects tides but less strongly due to greater distance.

Moon's magnetism attracts water — Wrong. The Moon has no significant magnetic field, and water isn't magnetically attracted anyway. Tides are caused by gravitational pull, not magnetism.