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': 'Example of artificial passive immunity? \nSelect and explain. \nA. Infection, B. Mother to child, C. Vaccine, D. Readymade immunoglobulin', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Infection - Natural active\nMother to child - Natural passive\nVaccine - Artificial active\nImmunoglobulins - Artificial passive', 'role': 'assistant'}]