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': 'Complement C1 is produced by \nSelect and explain. \nA. Macrophages, B. Liver, C. Intestinal epithelium, D. Spleen', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C1 - Intestinal epithelium\nC2, C4 - Macrophages\nC5, C8 - Spleen\nC3, C6, C9 - Liver', 'role': 'assistant'}]