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
The Fc piece of which Immunoglobulin fixes C1 complements? 
Select and explain. 
A. IgA, B. IgG, C. IgD, D. IgE
B: IgG
Answer: B: IgG 
Explanation: .