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: Anaesthesia
[{'content': 'Least MAC is of which inhalational agent? \nSelect and explain. \nA. Xenon, B. Halothane, C. Sevoflurane, D. Isoflurane', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. is \'a\' i.e., Halothane Agent MAC (%) Ether Halothane Enflurane Isoflurane Desflurane Sevoflurane Nitrous oxide 1.9 0.75 1.68 1.2 6.0 2.0 105 "Xenon has MAC of 71%" -- Morgan Methoxyflurone (MAC = 0.16%) > Trilene (0.2%) > Halothane (0.74%) > Chloroform (0.8%) > Isoflurane (1.15%)> Entlurane (1.68%) > Ether (1.92%) > Sevoflurane (2.0%) > Desflurane (6,0%) > Cyclopropane (9.2%) > N20 (104%).', 'role': 'assistant'}]