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
[{'content': 'The following constitutes approximately 75% of total immunoglobin in humans - \nSelect and explain. \nA. IgG, B. IgM, C. IgE, D. IgA', 'role': 'user'}, {'content': "Answer: A \nExplanation: 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>", 'role': 'assistant'}]