This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'Who introduced the vaccination for smallpox? \nSelect and explain. \nA. Edward Jenner, B. Louis Pasteur, C. Mathieu Orfila, D. John snow', 'role': 'user'}, {'content': 'Answer: A \nExplanation: "Edward Jenner introduced vaccination for smallpox with cowpox virus in 1798" Ref: Ananthanarayanan, 7/e, Page 5-7', 'role': 'assistant'}]