This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Opsnins is - 
Select and explain. 
A. C3a, B. 1gM, C. Carbothydrate binding proteins, D. Selections
A: C3a
Answer: A: C3a 
Explanation: Ans. is 'a' i.e., C3a Opsonin o A Substance capable of enhancing phagocytosis. o Complement (C3a) and antibodies are the two main opsonins.