The correct option is D Monocyte
Phagocytosis is the process of engulfing other cells or particles. Monocytes are the immune cells found in the blood that differentiates and fights with the bacteria, virus, and fungi by engulfing them and protect the body. Whereas platelets are the blood cells that help in the blood clotting. Basophil and eosinophil both are also blood cells, a type of WBC. They fight with pathogens by secreting chemical substance instead of engulfing them. Thus, the correct answer is option C.