This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
[{'content': 'Factor present in final common terminal complement pathway is rpt Q 38 \nSelect and explain. \nA. C3, B. C4, C. C5, D. Protein B', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Activation of the classical and alternative pathwaysleads to a common terminal pathway from C5 to C9. These complement components form the finalmembrane attack complex (MAC). ... complementfixation the combining of complement with the antigen-antibody complex, rendering the complement inactive, or fixed. Ref Robbins 9/e p40', 'role': 'assistant'}]