Final answer:
The respiratory macrophage is known as the alveolar macrophage or dust cell, which functions to keep the alveoli in the lungs clean by ingesting and digesting pathogens. The correct answer is c. Dust cell
Step-by-step explanation:
The respiratory macrophage you are asking about is known as the alveolar macrophage, sometimes referred to as a dust cell.
These macrophages are essential for the innate immune system and reside in the alveolar spaces of the lungs, where they ingest and digest pathogens and other particles, thereby keeping the alveoli clean.
Considering the given options, the correct answer is c. Dust cell, as it is specifically the type of macrophage associated with the respiratory system.
Other macrophages mentioned, such as Kupffer cells in the liver, histiocytes in connective tissue, and microglia in the central nervous system, perform similar functions but in different tissues of the body.