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: Physiology
[{'content': 'Secondary hyperparathyroidism due to Vitamin D deficiency shows: \nSelect and explain. \nA. Hypocalcemia, B. Hypercalcemia, C. Hypophosphatemia, D. Hyperphosphatemia', 'role': 'user'}, {'content': "Answer: C \nExplanation: Vitamin D deficiency decreases GI absorption of calcium and phosphate, causing hypocalcemia and also hypomagnesemia. Decreased serum calcium will stimulate PTH secretion leading to the elevation of calcium level towards normal along with phosphaturia. Phosphaturia inturn will lead to hypophosphatemia. Ref: Endocrine Physiology : Mosby Physiology Monograph Series, 3rd Edition, Page 101; Ganong's Review of Medical Physiology, 23rd Edition, Chapter 23; The Endocrine System at a Glance By Ben Greenstein, 3rd Edition, Page 117.", 'role': 'assistant'}]