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
An example of naturally acquired passive immunity is 
Select and explain. 
A. Hepatitis vaccination, B. Gamma globulin injection, C. Immune blood transfusion, D. Placental transfer of antibodies
D: Placental transfer of antibodies
Answer: D: Placental transfer of antibodies 
Explanation: None