What are the five types of WBC?

• A. Erythrocytes, leukocytes, thrombocytes, plasma, serum
• B. Platelets, RBCs, WBCs, plasma, serum
• C. B-cells, T-cells, NK cells, monocytes, eosinophils
• D. Neutrophils, lymphocytes, monocytes, eosinophils, basophils

Answer: (D)

The five major white blood cell types are neutrophils, lymphocytes, monocytes, eosinophils, and basophils. This grouping covers both granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (lymphocytes, monocytes), giving the complete set typically listed in a differential count.

Neutrophils are the most abundant and act as rapid responders to bacterial infection. Lymphocytes include B cells, T cells, and natural killer cells, driving adaptive immunity and targeted responses. Monocytes migrate into tissues and become macrophages or dendritic cells, handling phagocytosis and antigen presentation. Eosinophils help combat parasites and modulate allergic inflammation. Basophils release histamine and other mediators during allergic reactions and inflammatory processes.

The other options describe either different blood components (like red blood cells, platelets, plasma, serum) or only a subset of white cells, so they don’t represent the full five types of white blood cells.