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': 'Bone within a Bone appearance is not seen in \nSelect and explain. \nA. Osteopetrosis, B. Acromegaly, C. Hyperthyroidism, D. Hypercalcemia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Bone within a Bone appearance is seen in Hypothyroidism & Hypoparathyroidism.', 'role': 'assistant'}]