This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
[{'content': 'Bifurcation of trachea is at \nSelect and explain. \nA. Upper border of T5, B. Lower border of T4, C. Upper border of T4, D. Lower border of T5', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Trachea bifurcates at the lower border of fouh thoracic veebrae. <img src=" /> BA CHAURASIA\'S HUMAN ANATOMY VOLUME 1. 6TH EDITION.page no-280', 'role': 'assistant'}]