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': 'The most sensitive investigation for air embolism is: \nSelect and explain. \nA. Deceased tidal volume of CO2, B. TEE, C. Decreased tidal volume of NO2, D. Central venous pressure', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. TEE', 'role': 'assistant'}]