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: Microbiology
[{'content': 'Which one of the following is a major component in activation of the complement alternative pathway: September 2007 \nSelect and explain. \nA. C1, B. C2, C. C3, D. C4', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C: C3', 'role': 'assistant'}]