This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Opsonins are \nSelect and explain. \nA. C3a, B. IgM, C. Carbohydrates binding protein, D. Selectins', 'role': 'user'}, {'content': 'Answer: C \nExplanation: ref Robbins 8/e p51-53 ;7/e p59,9/e p78', 'role': 'assistant'}]