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: Anatomy
Posterior relation of hilum of lung ? 
Select and explain. 
A. Azygous vein, B. SVC, C. Vagus nerve, D. Arch of aoa
C: Vagus nerve
Answer: C: Vagus nerve 
Explanation: Vagus nerve