The five types of white blood cells are: which of the following is a correct listing?

• A. Eosinophil, basophil, neutrophil, lymphocyte, monocyte
• B. Neutrophil, erythrophil, leukocyte, basophil, eosinophil
• C. Neutrophil, basophil, eosinophil, granulocytes, acanthocyte
• D. Thrombocyte, monocyte, neutrophil, lymphocyte, eosinophil

Answer: (A)

White blood cells, or leukocytes, are classified into five main types: neutrophil, lymphocyte, monocyte, eosinophil, and basophil. This exact combination represents the complete set of standard leukocyte lineages found in mammals. The correct listing names these five, with no extras. Other options mix in terms that aren’t white blood cell types—for example, erythrophil isn’t a recognized WBC term (erythro- refers to red blood cells); leukocyte is the general category for all white blood cells, not a single type; granulocytes is a group that includes three types, not one type; acanthocytes are abnormal red blood cells; thrombocytes are platelets. So the only correct listing is neutrophil, lymphocyte, monocyte, eosinophil, and basophil.