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
[{'content': 'Small pox vaccine was invented by \nSelect and explain. \nA. Louis pasture, B. Edward Jenner, C. Paul Eugene, D. John snow', 'role': 'user'}, {'content': "Answer: B \nExplanation: Small pox vaccine Introduced by Edward Jenner in 1796, was the first successful vaccine to be developed Ref : Park's Textbook of Preventive and Social Medicine; 23rd edition", 'role': 'assistant'}]