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 45 year old man, known case of chronic renal failure develops rugger jersey spine. The probable cause is \nSelect and explain. \nA. Aluminium intoxication, B. Secondary hyperparathyroidism, C. Osteoporosis, D. Osteomalacia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Answer is B (Secondary Hyperparathyroidism): Rugger .Jersey Spine is characteristically found in secondary hyperparathyroidism (Renal osteodystrophy in CRF).', 'role': 'assistant'}]