This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
[{'content': 'a 45 year old man, known case of chronic renal failure develops rugger jersy spine. The probable Cause it- \nSelect and explain. \nA. aluminium intoxication, B. Secondary hyperparathyroidism, C. Osteoporosis, D. osteomalacia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans is option 2 Secondary hyperparathyroidism Rugger jersey spine results from Osteosclerosis which occurs in the setting of secondary hyperparathyroidism In CRF there is retention of phosphate Increase in phosphate inturn increases PTH leading to secondary hyperparathyroidism Ref Harrison 17/e p2388', 'role': 'assistant'}]