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
Membrane attack complex (MAC) in complement system is: 
Select and explain. 
A. C3b, B. C13, C. C5_9, D. C24
C: C5_9
Answer: C: C5_9 
Explanation: Ans. c. C5_9