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
Pin code indexof N2O is- 
Select and explain. 
A. 1,6, B. 2,5, C. 2,6, D. 3,5
D: 3,5
Answer: D: 3,5 
Explanation: Ans. is 'd' i.e., 3, 5 GasPin indexOxygen2,5Nitrous oxide3,5Cyclopropane3,6Air1.5Nitrogen1,4Entonox (50% O2 + 50% N2O)Single central (7)Carbon dioxide (< 7.5%)2,6~Carbon dioxide (> 7.5%)1,6