The correct option is B bone marrow
Immunity is defined as the ability of the host to fight against the disease-causing pathogens. The immune system in our body includes various lymphoid organs and a variety of cells which help in providing immunity.
Antibodies are proteins produced by the body in response to the entry of pathogens (bacteria, virus and protozoans). The part of the pathogen that elicits an immune response is called an antigen. Antibodies are produced in response to the antigen. These antibodies trap antigens and form the antigen-antibody complex. The antigen-antibody complex is later destroyed by the phagocytes.
The antibodies are produced by the B lymphocytes. B lymphocytes are a type of WBCs produced in the bone marrow and undergo maturation in the bone marrow itself.
T lymphocytes are also a type of WBCs produced in the bone marrow but undergo maturation in the thymus.
After maturation, both the B and T lymphocytes migrate to the secondary lymphoid organs like spleen, lymph nodes, tonsils, and Peyer's patches of the small intestine. In the secondary lymphoid organs, the B and T cells interact with antigens and become effector cells. The effector B cells are called plasma cells and they secrete antibodies.