This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
[{'content': 'In hyperparathyroidism all seen except- \nSelect and explain. \nA. Osteopetrosis, B. Osteoporosis, C. Cysts, D. Brown tumor', 'role': 'user'}, {'content': "Answer: A \nExplanation: Skeletal changes in hyperparathyroidism are Diffuse bone resorption, brown tumours, osteitis fibrosa cystica, cod fish spine deformities, pathological fracture, marrow fibrosis, X-ray findings in hyperparathyroidism Osteoporosis, subperiosteal resorption, tufting of middle phalanges of index and middle fingers, pinhead stippling, absence of lamina dura. Ref - Harrison's internal medicine 20e p2927-2928", 'role': 'assistant'}]