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': 'Cause of B/L recurrent laryngeal nerve palsy are -a) Thyroid Cab) Thyroid surgery c) Bronchogenic cancer d) Aortic aneurysm \nSelect and explain. \nA. ac, B. a, C. ab, D. bc', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Causes of bilateral recurrent laryngeal nerve paralysis are Thyroid surgery, Carcinoma thyroid, cancer cervical esophagus, cervical lymphadenopathy.', 'role': 'assistant'}]