This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2019, Subject name: Physiology
Normal anion gap is___ mmol/L? 
Select and explain. 
A. 6-Apr, B. 12-Jun, C. 24-Dec, D. 24-50
B: 12-Jun
Answer: B: 12-Jun 
Explanation: The cation normally measured is Na+, and the anions are usually Cl- and HCO3-. The "anion gap" is the difference between unmeasured anions and unmeasured cations and is estimated as Normal range: 8-16 mEq/L