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
Tracheal bifurcation is at which level of vertebra 
Select and explain. 
A. T4, B. T2, C. T1, D. T7
A: T4
Answer: A: T4 
Explanation: Trachea divides at the level of lower border of 4th thoracic vertebrae into 2 primary principal bronchus.