This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'A patient with diabetic nephropathy developed secondary hyperparathyroidism. Hyperparathyroidism is seen in all of the following conditions, EXCEPT: \nSelect and explain. \nA. Osteoporosis, B. Osteomalacia, C. Rickets, D. Chronic renal failure', 'role': 'user'}, {'content': "Answer: A \nExplanation: In chronic kidney disease, hyperphosphatemia and decreased renal production of 1,25-dihydroxycholecalciferol (1,252D3) initially produce a decrease in ionized calcium. The parathyroid glands are stimulated (secondary hyperparathyroidism) and may enlarge, becoming autonomous (teiary hyperparathyroidism). In osteomalacia and rickets, hypocalcemia acts as stimulus to secondary hyperparathyroidism. Ref: Shoback D., Sellmeyer D. (2011). Chapter 8. Metabolic Bone Disease. In D.G. Gardner, D. Shoback (Eds), Greenspan's Basic & Clinical Endocrinology, 9e.", 'role': 'assistant'}]