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: Pathology
[{'content': 'Which tumor is not seen in the anterior mediastinum - \nSelect and explain. \nA. Teratoma, B. Thymic tumors, C. Thyroid tumors, D. Neurofibroma', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]