This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': 'The Fc piece of which Immunoglobulin fixes C1 complements? \nSelect and explain. \nA. IgA, B. IgG, C. IgD, D. IgE', 'role': 'user'}, {'content': 'Answer: B \nExplanation: .', 'role': 'assistant'}]