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: Surgery
[{'content': "Sudeck's atrophy is associated with: \nSelect and explain. \nA. Osteoporosis, B. Osteophyte formation, C. Osteopenia, D. Osteochondritis", 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Osteopenia', 'role': 'assistant'}]