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
Which one of the following is a major component in activation of the complement alternative pathway: September 2007 
Select and explain. 
A. C1, B. C2, C. C3, D. C4
C: C3
Answer: C: C3 
Explanation: Ans. C: C3