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
"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 
Select and explain. 
A. Sir William Osier, B. William Harvey, C. Ronald Ross, D. Joseph Lister
A: Sir William Osier
Answer: A: Sir William Osier 
Explanation: (A) Sir William Osier