This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
[{'content': "'Second gas effect' is exeed by which of the following gas when coadministered with halothane: \nSelect and explain. \nA. Nitrous oxide, B. Cyclopropane, C. Nitrogen, D. Helium", 'role': 'user'}, {'content': 'Answer: A \nExplanation: (Ref: KDT 6/e p369) Concentration effect, second gas effect and diffusion hypoxia are seen with inhalational agents used in high concentrations (like N2O).', 'role': 'assistant'}]