This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Complement system, Subject name: Pathology
[{'content': 'Complement responsible for activation of bacterial lysis is: \nSelect and explain. \nA. C3a, B. C3b, C. C5-9, D. C5a', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Membrane attack complex is responsible for cell lysis It consist of C-5,6,7,8,9 complement proteins. This MAC get deposited on the cell membrane, and drills holes into it Thus, Cell become premeable to water and ions, leading to osmotic death (lysis)', 'role': 'assistant'}]