This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
The composition of ORS recommended by WHO is 
Select and explain. 
A. 3.5 g NaCl, B. 4.5 g NaCl, C. 2.9 g sodium-potassium citrate, D. 2.8 g sodium bicarbonate
C: 2.9 g sodium-potassium citrate
Answer: C: 2.9 g sodium-potassium citrate 
Explanation: None