This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'The immunoglobulin least commonly involved in Multiple Myeloma is: \nSelect and explain. \nA. IgG, B. IgM, C. IgA, D. IgD', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Answer is D (IgD) The M component in Multiple Myeloma can be made up of the immunoglobulins IgG, IgM, IgD, IgA, and IgE; light chains alone; or heavy chains alone. IgG Myeloma is the most common form of Multiple Myeloma while Ig D (2%) and IgE (Rare) are the least common.', 'role': 'assistant'}]