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: Radiology
[{'content': 'Tracheal bifurcation on X–ray corsponds to – a) T5T6b) T4T5c) Sternal angled) Thoracic inlet \nSelect and explain. \nA. a, B. bc, C. ac, D. ad', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Tracheal bifurcation (carina) is located at about 4th thoracic vertebral body or T4-T5 disc space posteriorly and sternal angle of louis anteriorly.', 'role': 'assistant'}]