This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Larynx, Subject name: ENT
Bilateral recurrent laryngeal nerve is most commonly affected in- 
Select and explain. 
A. Neck trauma, B. Bronchogenic carcinoma, C. Carcinoma esophagus, D. Post thyroid surgery
D: Post thyroid surgery
Answer: D: Post thyroid surgery 
Explanation: Ans. is 'd' i.e., Post thyroid surgery Causes of recurrent laryngeal nerve (vocal cord or abductor) paralysis* Depending upon the cause, vocal cord paralysis may be unilateral or bilateral.* In unilateral paralysis, left recurrent laryngeal nerve is more prone to paralysis compared to the right one because of its much longer course.* Most common overall cause of vocal cord paralysis is iatrogenic in origin following surgery, most commonly thyroidectomy.* Most common cause of unilateral left vocal cord paralysis is bronchial carcinoma at the left hilum.