Q.
Given below is the diagram of human lymphatic system, where A, B, C and D are lymphoid organs. Select incorrect option regarding the lymphoid organs labelled as A, B, C and D.
'A'-lymph nodes, 'B'-Thymus, 'C'-spleen, 'D'-Bone marrow. Thymus and bone marrow are the primary lymphoid organs where maturation of T-cells and B-cells take place respectively. Lymph nodes and spleen are the secondary lymphoid organs where T-cells and B-cells undergo proliferation and differentiation.