This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Body fluid compaments, Subject name: Physiology
Which diagram represents the changes (after osmotic equilibrium) in extracellular and intracellular fluid volumes and osmolarities after the infusion of 3% NaCl? 
Select and explain. 
A. A, B. B, C. C, D. D
C: C
Answer: C: C 
Explanation: A 3% solution of NaCl is hypeonic, and when infused into the extracellular fluid, it would raise osmolarity, thereby causing water to flow out of the cells into the extracellular fluid until osmotic equilibrium is achieved. In the steady state, extracellular fluid volume would increase, intracellular fluid volume would decrease, and osmolarity of both compaments would increase.