This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardio thoracic surgery  , Subject name: Surgery
[{'content': 'Tumours of anterior mediastinum include the following except \nSelect and explain. \nA. Thymoma, B. Lymphoma, C. Germ cell tumour, D. Schwannoma', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Schwannoma is a benign nerve sheath tumor arising from Schwann(neurilemmal)cells.Anterior mediastinal tumors include retrosternal goitre,aoic arch aneurysm,lymph node enlargement,thymoma,teratomas,dermoid,Pleuro-pericardial cyst.', 'role': 'assistant'}]