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: Anaesthesia
[{'content': 'Placement of a double lumen tube (DLT) is best confirmed by: \nSelect and explain. \nA. Clinically by Auscultation, B. Fibreoptic bronchoscopy, C. Capnography, D. Chest radiography', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B. i.e. Fiber optic bronchoscopy', 'role': 'assistant'}]