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: Surgery
[{'content': 'M. C. anterior mediastinum tumor is - \nSelect and explain. \nA. Thymoma, B. Neurogenic Fibroma, C. Lymphoma, D. Meningocele', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Remember\nMost common mediastinal → mass\xa0Neurogenic tumors\nMost common Ant. mediastinal mass\xa0→\xa0Thymoma\nMost common Middle mediastinal mass\xa0→\xa0Bronchogenic & pleuropericardial cysts\nMost common Posterior mediastinal mass\xa0→\xa0Neurogenic tumor\nMost common malignant mass of mediastinum\xa0→\xa0Lymphomas\nMost common mediastinal mass in children\xa0→\xa0Neurogenic tumor', 'role': 'assistant'}]