This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharynx, larynx and trachea and cranial nerves 3,4,6, Subject name: Anatomy
[{'content': 'Young singer at local music theatre complains of vocal difficulties. On examination, she is unable to abduct vocal cords during quiet breathing. Which of the following muscles is most likely to be paralyzed? \nSelect and explain. \nA. Vocalis muscle, B. Cricothyroid muscle, C. Oblique arytenoid muscle, D. Posterior cricoarytenoid muscle', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Posterior cricoarytenoid muscle is the only muscle that abducts vocal cords during quiet breathing. All other laryngeal muscles adduct the vocal cords.', 'role': 'assistant'}]