This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Congenital Diseases of Larynx, Subject name: ENT
Abductor of vocal cord is: 
Select and explain. 
A. Posterior cricoarytenoid, B. Lateral cricoarytenoid, C. Cricothyroid, D. Thyroarytenoid
A: Posterior cricoarytenoid
Answer: A: Posterior cricoarytenoid 
Explanation: The Posterior cricoarytenoid is the only abductor of the true vocal cord.