Where do B cells develop and mature?

• A. Spleen
• B. Red bone marrow
• C. Thymus
• D. Lymph nodes

Answer: (B)

B cells develop and mature in the red bone marrow. This is where hematopoietic stem cells give rise to B lymphocytes and undergo the initial maturation and selection needed to produce a diverse B cell receptor repertoire. After maturation, B cells migrate to secondary lymphoid organs like the spleen and lymph nodes to encounter antigens and become activated. The thymus is the maturation site for T cells, not B cells, while the spleen and lymph nodes house mature B cells for immune responses rather than their development.