Answer:
The correct answer will be option-B.
Explanation:
Lymphocytes are a type of white blood cells or leukocytes which can be easily distinguished as they have a single round nucleus.
Lymphocytes act as immune cells in the body as they help in providing immunity. These lymphocytes upon maturation get differentiated into two types: B cell and T cell.
The B cell produces specific antibodies in response to the foreign bodies called antigen. They attach with the antigen and mark the antigen for destruction. This takes place in the blood thus provides the humoral immunity.
T cell recognize and respond to the antigen directly by killing the cell with antigen or indirectly by producing lymphokines to kill the cell. This provides immunity tat with the cellular level.
Thus, Option-B is the correct answer.
