This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General surgery, Subject name: Surgery
Concentration of Na (meq/I) in normal saline is ? 
Select and explain. 
A. 77, B. 109, C. 130, D. 154
D: 154
Answer: D: 154 
Explanation: sodium in various fluids normal saline - 154mmol/l ECF - 142mmol/l lactated ringer - 130mmol/l