This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
Gases for Pneumoperitoneum 
Select and explain. 
A. CO2, B. N2, C. O2, D. Room air
A: CO2
Answer: A: CO2 
Explanation: CO2 is commonly used to create pneumoperitoneum as it is readily available, is cheaper, suppresses the combustion, is easily absorbed by tissues, has a high diffusion coefficient and is quickly released respiration. Other gases used are: Air, nitrous oxide, helium, argon. Reference : page 1183 SRB's manual of surgery 5th edition