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: ENT
[{'content': 'A patient with a Pancoast tumor develops a loss of voice after radiation. It is due to - \nSelect and explain. \nA. Vocal cord infiltration with secondaries, B. Involvement of recurrent laryngeal nerve, C. Irradiation to vocal cords, D. Radiation stenosis of larynx', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]