The correct answer is option D. the adaptive immune system.
Explanation:
The adaptive immune system is the immune system that takes place after the first exposure to a specific antigen either from vaccination or a pathogen. Adaptive responses are of two types: the cell-mediated and humoral immune response, the cell-mediated immune response occurs with the help of T cells, and where is humoral immune response is B cells and antibodies.
Vaccination targets the adaptive immune system as they produce antibodies against the pathogen provided by vaccination.
Thus, the correct answer is option D. the adaptive immune system.
