This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax- wall and Bronchopulmonary segment, Subject name: Anatomy
[{'content': "A 46-year-old patient comes to doctor's OPD with complains of chest pain and headache. His computed tomography (CT) scan reveals a tumor located just superior to the root of the right lung. Blood flow in which of the following veins is most likely blocked by this tumor? \nSelect and explain. \nA. Hemiazygos vein, B. Arch of the azygos vein, C. Right subclan vein, D. Right brachiocephalic vein", 'role': 'user'}, {'content': 'Answer: B \nExplanation: The azygos vein arches over the root of the right lung and empties into the SVC. Other veins do not pass over the root of the right lung.', 'role': 'assistant'}]