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': "3 days post colle's fracture. a person is unable to extend his thumb due to \nSelect and explain. \nA. Rupture of extensor pollicis longus tendon, B. Volkman's Ischemic contracture, C. Radial nerve injury, D. Finger stiffness", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]