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: Microbiology
[{'content': 'The type of immunoglobulin most commonly\nincreased in multiple myeloma is \nSelect and explain. \nA. IgG, B. IgA, C. IgM, D. IgD', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]