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
Brown tumours are seen in: 
Select and explain. 
A. Hyperparathyroidism, B. Pigmented villonodular synovitis, C. Osteomalacia, D. Neurofihromatosis
A: Hyperparathyroidism
Answer: A: Hyperparathyroidism 
Explanation: None