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: ENT
The most common cause of vocal cord palsy is: 
Select and explain. 
A. Total thyroidectomy, B. Bronchogenic carcinoma, C. Aneurysm of aoa, D. Tubercular lymph nodes
A: Total thyroidectomy
Answer: A: Total thyroidectomy 
Explanation: Thyroidectomy was the single most common surgical cause for unilateral vocal cord palsy, followed by other nonthyroid neck surgeries (20%) and anterior cervical decompression (18.3%). Conclusion: The most common cause for unilatera lvocal cord palsy is idiopathic.