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 of aoa, D. Tubercular lymph nodes', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Thyroidectomy was the single most common surgical cause for unilateral vocal cord palsy, followed by other nonthyroid neck surgeries (20%) and anterior cervical decompression (18.3%). Conclusion: The most common cause for unilatera lvocal cord palsy is idiopathic.', 'role': 'assistant'}]