This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Body composition and Acid base Balance, Subject name: Pediatrics
A Normal anion gap metabolic acidosis occurs in patients with? 
Select and explain. 
A. Diabetic ketoacidosis, B. Methyl alcohol poisoning, C. Diarrhea, D. Acute kidney injury
C: Diarrhea
Answer: C: Diarrhea 
Explanation: Diarrhea and Renal tubular acidosis (A) are two impoant causes of normal anion gap metabolic acidosis.