Answer: a. has a lag period while B cells proliferate and differentiate into plasma cells
Step-by-step explanation:
When the body comes in contact with foreign antigen for first time it is accompanied by primary immune responses, a lag period occurs in which no antibody is produced but activated B cells are transformed into plasma cells, this is called lag phase. The lag period may be as short as 2-3 days but is sometimes longer.
white blood cells consist of B cells which are formed in the bone marrow. Growing B cell (after first exposure) produces several copies of one type of antigens as a surface antigen receptor. The entire population of B cells has the ability to directly bind to millions of different antigens. If the antibody on a B cell's surface bind to an antigen, the cell will be primed to undergo proliferation and differentiation.
Hence, the correct option is a.