Answer:
The correct answer is the primary response.
Explanation:
Immune response to an antigen can be categorized as a primary response or the secondary response, Primary response takes place as a result of first time exposure to the antigen. Naïve B-cell and T-cell are the cells of the primary response action. The lag phase is generally four to seven days however in some cases it can be weeks or months.
The primary response is slower in comparison or the secondary response. IgM is main and produced first in the primary response. Lymph nodes and spleen are sites for the primary response.
Thus, the correct answer is the primary response.
