This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Social & Preventive Medicine
[{'content': '"Humanity has hut three great enemies: fever; famine and war; of these by far the greatest, by far the most terrible, is fever.99 It is a saying of \nSelect and explain. \nA. Sir William Osier, B. William Harvey, C. Ronald Ross, D. Joseph Lister', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (A) Sir William Osier', 'role': 'assistant'}]