Answer:
A. B cells
Explanation:
B cells are involved in the specific immune response that exhibits specificity, memory and self-non-self distinction. This immune response is also called as adaptive immunity. B cells are produced in the bone marrow. An encounter of B cells with antigen activates them for multiplication.
The activated B cells produce plasma cells which in turn produce specific antibodies that bind to the specific antigens and start the adaptive immune response.
