This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunity, Subject name: Pathology
What is the formula for lytic complex in complement system? 
Select and explain. 
A. C5a, B. C5-9, C. C3b, D. C3a
B: C5-9
Answer: B: C5-9 
Explanation: Ans. is 'b' i.e., C5-9 * C5-9 Called membrane attack complex (MAC). It forms channel in the lipid membrane and causes cell lysis (including bacteria).