This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oral cavity & Oesophagus, Subject name: ENT
[{'content': 'The bifurcation of trachea occurs most commonly at \nSelect and explain. \nA. T3, B. T5, C. T7, D. T9', 'role': 'user'}, {'content': 'Answer: B \nExplanation: "The level of bifurcation of the trachea varies from the lower third of the fouh to the middle of the seventh thoracic veebrae. The average position is at the level of the lower third of the fifth thoracic veebra.Ref: PL Dhingra, Diseases of Ear, Nose & Throat, 7th edition, pg no. 319', 'role': 'assistant'}]