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
[{'content': 'Which of the following is caused by deficiency of complement C3 and C3b? \nSelect and explain. \nA. Hereditary angioneurotic edema, B. SLE, C. Severe recurrent pyogenic infection, D. Collagen vascular disease', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C1 inhibitor deficiency is associated with hereditary angioneurotic oedema. C3 deficiency is associated with severe recurrent pyogenic infection. Deficiency of C1 to C4 is associated with SLE Ref: Textbook of Microbiology by Ananthanarayanan, 6th Editio, Page 108.', 'role': 'assistant'}]