This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concept of health and disease, Subject name: Social & Preventive Medicine
Smallpox vaccine was introduced by 
Select and explain. 
A. Paul Ehrlich, B. Robe Koch, C. Louis Pasteur, D. Edward Jenner
D: Edward Jenner
Answer: D: Edward Jenner 
Explanation: Edward Jenner discovered smallpox vaccine in1796