This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
A normal-anion-gap metabolic acidosis occurs in patients with 
Select and explain. 
A. Diarrhoea, B. Diabetic ketoacidosis, C. Methyl alcohol poisoning, D. Acute renal failure
A: Diarrhoea
Answer: A: Diarrhoea 
Explanation: During diarrhea, there is a loss of water, sodium, bicarbonate, and potassium in the fecal fluid leading to dehydration.Contraction of the extracellular fluid causes hyperchloremia.Hence the decrease in HCO3- is compensated by the corresponding increase in Cl- causing normal AG Metabolic acidosis. High anion gap acidosisNormal anion gap acidosisLactic acidosisKetoacidosisToxin ingestionAcute & chronic renal failure DiarrheaFistulaUretero-sigmoidostomyProximal renal tubular acidosis Carbonic anhydrase inhibitorsMineralocoicoid deficiencyRef: Harrison's 18/e p368