This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Complement component involved in both classical and alternate pathway: 
Select and explain. 
A. C1, B. C2, C. C3, D. C5
C: C3
Answer: C: C3 
Explanation: Ans. C. C3a. C3 is involved in both classical and alternate complement pathways.b. Activation of C3 is the central process in complement cascade.c. Activation of C3 is achieved by C42 (classical C3 convertase) in classical pathway.d. The activation of C3 without prior participation of C142 is known as alternate pathway.