Osmosis drives water into the hypertonic tube Steps:

• Osmosis moves water across a semi-permeable membrane from hypotonic (low solute) to hypertonic (high solute) regions.
• Tube X contains concentrated salt solution (hypertonic), placed in pure water (hypotonic).
• Water enters tube X, raising the liquid height.
• Inflow dilutes the salt solution inside tube X, lowering its concentration.

Why C is correct:

• Osmosis definition: net water movement into hypertonic side increases volume (height) while diluting solute concentration.

Why the others are wrong:

• A: Height decreases only if water exits (hypotonic inside), but setup is opposite.
• B: Concentration increases via evaporation or solute addition, not osmosis here.
• D: Height decreases and concentration increases contradict water inflow.

Final answer: C