This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
[{'content': 'ETHER DAY is celebrated on \nSelect and explain. \nA. 20-Oct, B. 16-Oct, C. 20-Nov, D. 16-Nov', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ether Day," Friday 16 October 1846 marks the first successful demonstration of the inhalation of ether vapour as a means of overcoming pain of surgery by the dentist William Thomas Green Moon Ref ganong\'s review of medical physiology 25e 561', 'role': 'assistant'}]