This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Surgery
[{'content': 'Most common and best gas for laparoscopy: \nSelect and explain. \nA. CO2, B. N2, C. Air, D. O2', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: a (CO2) Ref:Bailey, 24th ed,p. 107CO is the gas used to create pneumoperitoneumMethods for creating pneumoperitoneum-Open- more cumbersome, but more efficientClosed- blind puncture"It was desirable that intraabdominal pressure should be between 12-14 mm Hg and should never be allowed to exceed 20 mm Hg.- (Ajay Yadav, p. 168).', 'role': 'assistant'}]