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
The following constitutes approximately 75% of total immunoglobin in humans - 
Select and explain. 
A. IgG, B. IgM, C. IgE, D. IgA
A: IgG
Answer: A: IgG 
Explanation: IgG is the main serum immunoglobulin consisting of 80% of the total. equally distributed between intravascular and extravascular compaments. The normal serum concentration of IgG is about 8-16 mg per ml. Reference : Anathanarayan & paniker's 9th edition, pg no: 96, <\p>