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': 'Early and reliable indication of air embolism during anaesthesia can be obtained by continuous monitoring of: \nSelect and explain. \nA. ECG, B. Blood pressure, C. End Tidal CO2, D. Oxygen saturation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: End Tidal CO2', 'role': 'assistant'}]