This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney Stones & Renal Tubular Acidosis, Subject name: Medicine
[{'content': 'Nephrocalcinosis is seen in all except? \nSelect and explain. \nA. Polycystic kidney, B. Hyperparathyroidism, C. Medullary sponge kidney, D. Renal tubular acidosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Causes of Nephrocalcinosis Medullary sponge kidney Hyperparathyroidism/ Hypoparathyroidism Renal tubular acidosis Renal tuberculosis Hyperoxaluria Milk-alkali syndrome Sarcoidosis', 'role': 'assistant'}]