This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluid & Electrolyte, Subject name: Medicine
Normal anion gap is - 
Select and explain. 
A. 8-10mmol/L, B. 10-12 mmol/L, C. 12-16 mmol/L, D. 16-20 mmol/L
B: 10-12 mmol/L
Answer: B: 10-12 mmol/L 
Explanation: (B) (10-12 mmoI/L) (365-H 18th) (443 - Davidson 21st)* Normal anion gap is 10 to 12 mmol/L* * Calculated as follows : AG = Na+ - (C1-+ Co-3)* It consist of for the most part of protein* ** in the anion form HP04" S04~) and organic acids. The unmeasured cations are K+, Ca+ or Mg+.Normal (6-12 meq) anion gap* Loss of HCO3 - Diarrhoea- Recovery from diabetic Ketoacidosis- Pancreatic fluid loss ileostomy (unadopted)- Carbonic anhydrase inhibitors* Chloride retension I. Renal tubular acidosisII. Ileal loop bladder* Administration of HC1 equivalent or NH4C1 Arginine and lysine in Parenteral nutritionCauses of High anion gap metabolic acidosis* Lactic acidosisToxins* Ketoacidosis- Ethylene glycol- Diabetic- Methanol- Alcoholic- Salicylates (Aspirin)- Starvation- Propylene glycol - Pyroglutamic acid Renal failure (acute and chronic.