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 of the following determines the class of immunoglobulin? \nSelect and explain. \nA. L-chain, B. H-chain, C. J-chain, D. Variable region', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Based on the constant region of the heavy chains (g, a, m, d and e);Ig has been classified into five types; lgG, IgA, IgM, IgD and IgE respectively. Differences inheavy chain (H chain) polypeptides allow these immunoglobulinsto function in different types of immune responses and at paicular stages of the immune response.', 'role': 'assistant'}]