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: Pathology
The complement is fixed best by which of the following immunoglobulins - 
Select and explain. 
A. IgG, B. IgM, C. IgA, D. IgD
B: IgM
Answer: B: IgM 
Explanation: Ans. is 'b' i.e., IgMIgM is the most effective antibody to fix complement.