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': 'Thymoma is associated with - \nSelect and explain. \nA. Myasthenia gravis, B. Scleroderma, C. Oesophageal atresia, D. Hypergammaglobulinemia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]