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
The thoracic duct crosses the posterior mediastinum at the level of which vertebra- 
Select and explain. 
A. T5, B. T6, C. T7, D. T8
A: T5
Answer: A: T5 
Explanation: At the level of T5, thoracic duct crosses from right to left.