Which of the following cell produces histamin and heparin ? a) Plasma cells b) WBC c) Macrophage cells d) Mast cells

The correct answer is (d) Mast cells. Mast cells are specialized connective tissue cells that produce and store histamine (a key mediator of allergic reactions and inflammation) and heparin (a natural anticoagulant). While basophils (a subtype of white blood cells, WBC) also produce histamine and heparin, they are not listed as an option here. Plasma cells (a) produce antibodies, and macrophages (c) are involved in phagocytosis and cytokine release, not histamine or heparin synthesis. Thus, mast cells are the primary cells responsible for these functions among the given options.