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: Radiology
[{'content': 'Subperiosteal resorption and thickness of skull is increased in: \nSelect and explain. \nA. Rickets, B. Osteomalacia, C. Hyperparathyroidism, D. Thalassemia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Hyperparathyroidism', 'role': 'assistant'}]