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': 'The most common cause of vocal cord palsy is - \nSelect and explain. \nA. Total thyroidectomy, B. Bronchogenic carcinoma, C. Aneurysm aorta, D. Tubercular lymph nodes', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In unilateral paralysis, left recurrent laryngeal nerve is more prone to paralysis compared to the right one because of its much longer course.\nMost common overall cause of vocal cord paralysis is iatrogenic in origin following surgery, most commonly thyroidectomy.\nMost common cause of unilateral left vocal cord paralysis is bronchial carcinoma at the left hilum.', 'role': 'assistant'}]