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': 'Which of the following is not a true association of thymoma ? \nSelect and explain. \nA. Myasthenia gravis may be seen, B. Hypergrammaglobulinemia, C. Pure red cell aplasia, D. Superior mediastinal compression syndrome', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The usual association is hypogamaglobuthemia not hyperglobulinemia.', 'role': 'assistant'}]