Which of the following is an isotonic solution?

Correct option is D

Ans. (d) 0.9% NaCl Sol. 0.9% Sodium Chloride (NaCl) is isotonic to human blood plasma, meaning it has the same osmotic pressure and doesn't cause cells to shrink or swell when administered.
Explanation of each option:
· (a) 0.1% NaCl – Hypotonic; causes cells to swell.
· (b) 1% NaCl – Hypertonic; can cause cells to shrink.
· (c) 0.45% NaCl – Hypotonic; used in specific conditions.
· (d) 0.9% NaCl – Correct. Isotonic; used commonly in IV fluids.