Which situation is an example of an isotonic solution with respect to a human red blood cell?

• A. A red blood cell placed in pure water swells and may lyse.
• B. A red blood cell placed in $3.0\%$ $N_{a}Cl$ ($aq$) shrinks.
• C. A red blood cell placed in $0.10\%$ $N_{a}Cl$ ($aq$) swells.
• D. A red blood cell placed in $0.90\%$ $N_{a}Cl$ ($aq$) shows no net change in size.

Answer: (D)