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 level, which is specifically elevated in autoimmune pancreatitis is which of the following? \nSelect and explain. \nA. IgM, B. IgE, C. IgG4, D. IgG2', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Serum IgG4 is elevated at least twofold higher than 135 mg/dL in those with autoimmune pancreatitis. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 2644', 'role': 'assistant'}]