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
[{'content': 'Deficiency of C1 inhibitor can produce \nSelect and explain. \nA. Hereditary angioneurotic edema, B. SLE, C. No disease, D. Pyogenic infections', 'role': 'user'}, {'content': 'Answer: A \nExplanation: C3 def can lead to recurrent pyogenic infections C1 inhibitor deficiency can lead to hereditary angioneurotic edema Ref: Textbook of Microbiology Baveja 5th ed Pg 125', 'role': 'assistant'}]