This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
[{'content': 'The commonest site for extra gonadal germ cell tumour \nSelect and explain. \nA. Retroperitoneum, B. Sacrococcygeal region, C. Pineal gland, D. Mediastinum', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Anterior Mediastinal Masses Thymoma (MC in anterior mediastinum) Lymphoma Germ cell tumors. Thyroid and parathyroid masses Bronchogenic cyst Aneurysm Germ cell tumors constitute 11% of Total tumors in anterior mediastinum Ref: Sabiston 20th edition Pgno : 1608', 'role': 'assistant'}]