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: Unknown
[{'content': 'Which of the following muscle produces abduction of vocal cord? \nSelect and explain. \nA. Posterior cricoarytenoid, B. Lateral cricoarytenoid, C. Cricothyroid, D. Oblique arytenoids', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Intrinsic muscles of larynx\n\xa0\nExceptions: 1. All are paired except transverse arytenoid\n\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 2. All lie internally except cricothyroid\nA) Muscles which modify rima glottidis', 'role': 'assistant'}]