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: Orthopaedics
[{'content': "4 year old child complains of painful  limb, the likely cause \nSelect and explain. \nA. Poliomyelitis, B. Infantile coxa vara, C. Perthe's disease, D. CTEV", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]