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: Unknown
[{'content': 'Which gas is most commonly used with pneumatic retinopexy - \nSelect and explain. \nA. SF6, B. C3F8, C. CO2, D. N3', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.c., SF6 o Sulfur hexafluoride gas (SF6) is most commonly used with pneumatic retinopexy.", 'role': 'assistant'}]