This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Introduction, Subject name: Pediatrics
Active immunity is not acquired by which of the following ? 
Select and explain. 
A. Infection, B. Vaccination, C. Immunoglobulin transfer, D. Subclinical infection
C: Immunoglobulin transfer
Answer: C: Immunoglobulin transfer 
Explanation: - Immunoglobulins - provide passive immunity Active immunity: - Protective response mounted by a person's own immune system after clinical / subclinical infection / vaccination. - Comprises humoral / cellular immune responses Passive immunity: - Ready-made protection against disease provided by introduction of preformed animal/ human antibodies into the human body Passage of IgG from mother to fetus through placenta Transmission of secretory IgA in breast milk Administration of Antisera