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': 'An example of naturally acquired passive immunity is \nSelect and explain. \nA. Hepatitis vaccination, B. Gamma globulin injection, C. Immune blood transfusion, D. Placental transfer of antibodies', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]