Final answer:
C) Macrophages are the immune cells that have the ability to phagocytize pathogens and release chemicals to promote inflammation; they also serve as antigen-presenting cells.
Step-by-step explanation:
The type of immune system cell that can both phagocytize pathogens and produce chemicals that promote inflammation is the macrophage. Macrophages develop from monocytes and are highly efficient phagocytes able to engulf a significant number of pathogens or other cells. Moreover, macrophages produce various chemicals such as enzymes, complement proteins, and cytokines. They not only clean up tissues by removing worn-out cells and debris but also function as antigen-presenting cells (APCs), activating the adaptive immune system. It's essential to note other cells involved in the immune response, such as natural killer cells and neutrophils. Natural killer cells are a type of lymphocyte that targets cancerous or virus-infected host cells, while neutrophils are the most numerous and rapidly respond to infections, though their lifespan after phagocytosis is short.