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': 'Commonest symptom associated with thoracic outlet syndrome is - \nSelect and explain. \nA. Intermittent claudication, B. Pain on radial distribution, C. Pain in ulnar distribution, D. Gangrene', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]