This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head & Neck, Subject name: Anatomy
Abductors of vocal cord is 
Select and explain. 
A. Lateral cricoarytenoids, B. Posterior cricoarytenoids, C. Thyro arytenoids, D. Cricothyroids
B: Posterior cricoarytenoids
Answer: B: Posterior cricoarytenoids 
Explanation: i.e. (Posterior cricoarytenoids): (243-BDC-3-5th ed)Muscles acting on the Larynx|| |Movements Muscles1. Elevation of larynx Thyrohyoid, mylohyoid2. Depression of larynx Sternothyroid, sternohyoid3. Opening of larynx Thyroepiglotticus4. Closing inlet of larynx Aryepiglotticus5. Abductor of vocal cords Posterior cricoaryteroids only6. Adductor of vocal cords Lateral cricoarytenoids, transverse oblique arytenoids7. Tensor of vocal cords Cricothyroids8. Relaxor of vocal cords Thyroarytenoids(i) Cricothyroid is supplied by external laryngeal nerve(ii) Rest of the intrinsic muscle - recurrent laryngeal nerve