This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluid and electrolytes, Subject name: Pediatrics
Sodium content in mmol/L in WHO oral rehydration solution is 
Select and explain. 
A. 20, B. 75, C. 90, D. 111
B: 75
Answer: B: 75 
Explanation: Composition of WHO recommended ORS : Reduced osmolarity ORS grams/litre Reduced osmolarity ORS mmol/litre Sodium chloride 2.6 Sodium 75 Glucose, anhydrous 13.5 Chloride 65 Potassium chloride 1.5 Glucose, anhydrous 75 Trisodium citrate, dihydrate 2.9 Potassium 20 Citrate 10 Total Osmolarity 245 Reference: GHAI Essential pediatrics, 8th edition