The question lists four blood cell types and asks which pair clears antigen-antibody complexes from the blood. Let's check each cell type's actual job.
- Platelets (A): these cell fragments plug damaged blood vessels and start clotting. They do not engulf or clear immune complexes.
- Eosinophils (B): these white blood cells release granules and help mop up antigen-antibody complexes, particularly in allergic and parasitic reactions, so they take part in clearing these complexes.
- Monocytes (C): once they move into tissue and become macrophages, these cells engulf antigen-antibody complexes by phagocytosis, which is the main way these complexes get cleared from circulation.
- RBC (D): red blood cells carry oxygen and carbon dioxide. They have no phagocytic ability and play no part in clearing immune complexes.
Only eosinophils and monocytes actually take part in removing these complexes, since both can engulf or break down antibody-bound antigens, while platelets and RBCs are built for entirely different jobs.
Let's summarize:
- Monocytes, once turned into macrophages, phagocytose antigen-antibody complexes.
- Eosinophils also help clear these complexes, especially in allergic settings.
- Platelets and RBCs have no role in this clearance.
So the pair responsible is B and C, eosinophils and monocytes, option (2).