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': 'Smallpox vaccine was introduced by: \nSelect and explain. \nA. Paul Ehrlich, B. Robert Koch, C. Louis Pasteur, D. Edward Jenner', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. (d) Edward Jenner* Edward Jenner discovered Smallpox vaccine in 1796- Smallpox vaccine was the 'First Vaccine' to be dis- covered- Smallpox is the 'First and Only' disease to be eradicated - Term 'Vaccination' was coined by Edward JennerALSO REMEMBER* Paul Ehrlich coined terms 'Chemotherapy' and 'Auto-immunity' and giving 'Magic Bullet for Syphilis- Salvarsan'", 'role': 'assistant'}]