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
Immunoglobulin found in B lymphocyte - 
Select and explain. 
A. IgA, B. IgE, C. IgG, D. IgD
D: IgD
Answer: D: IgD 
Explanation: Immunoglobulin D (IgD) is an antibody isotype that makes up about 1% of proteins in the plasma membranes of immature B-lymphocytes where it is usually coexpressed with another cell surface antibody called IgM. Reff: www.mayoclinic.com