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': 'Which immunoglobulin has no known function but is present on the surface of B lymphocytes and it may function as an antigen receptor? \nSelect and explain. \nA. IgA, B. IgE, C. Ig D, D. IgM', 'role': 'user'}, {'content': 'Answer: C \nExplanation: IgD antibody consists of two light chains and two heavy chains. Its role is not known but can be found on the surface of lymphocytes where it may act as a surface receptor. Ref : Ananthanarayana textbook of Microbiology 9th edition Pgno : 98', 'role': 'assistant'}]