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': 'Mediastinoscope can be visualize all of the following lymphnode except ? \nSelect and explain. \nA. Right paratracheal lymphnode, B. Aorto pulmonary window lymphnode, C. Anterior tracheal, D. Subcarinal', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]