This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous General Anesthesia, Subject name: Anaesthesia
[{'content': 'Which gas is most commonly used in laparoscopy: \nSelect and explain. \nA. O2, B. CO2, C. N2O, D. N2', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' CO2", 'role': 'assistant'}]