This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Sodium and Potassium, Subject name: Pediatrics
[{'content': 'An 11 year child with failure to thrive, metabolic acidosis with increased anion gap. Not true regarding the differential diagnosis: \nSelect and explain. \nA. Insulin dependent diabetes mellitus, B. Chronic renal failure, C. Renal tubular acidosis, D. Inborn errors of metabolism', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Renal tubular acidosis - normal anion gap acidosis', 'role': 'assistant'}]