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
True statement regarding extracellular fluid to intracellular fluid is: 
Select and explain. 
A. ECF is rich in K+, B. ECF volume is twice that of the ICF, C. ECF is rich in organic anion, D. There is high sodium and low potassium in ECF
D: There is high sodium and low potassium in ECF
Answer: D: There is high sodium and low potassium in ECF 
Explanation: Option A is incorrect. ICF is rich in K+; ECF has a low concentration of K+. Option B is incorrect. ICF volume (28 L) is twice the volume of ECF (14 L). Option C is incorrect. ICF is rich in organic anions, the proteins. Other anions in ICF are inorganic phosphate. Option D is correct. There is high sodium and low potassium in ECF.