This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology Pa 1 (Immune Response, Antigen-Antibody Reactions, Hypersensitivity, Structure of Immune System, Immunodeficiency Disorders), Subject name: Microbiology
[{'content': 'Which immunoglobulin is scarce in human serum - \nSelect and explain. \nA. IgA, B. IgG, C. IgM, D. IgE', 'role': 'user'}, {'content': 'Answer: D \nExplanation: IgG has maximum serum concentration (12 mg/mL) and IgE has minimum serum concentration (0.00004mg/mL).', 'role': 'assistant'}]