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: Pathology
[{'content': 'Brown tumours are seen in: \nSelect and explain. \nA. Hyperparathyroidism, B. Pigmented villonodular synovitis, C. Osteomalacia, D. Neurofihromatosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]