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: Anatomy
[{'content': 'What is the uppermost structure in left lung hilum? \nSelect and explain. \nA. Pulmonary aery, B. Pulmonary vein, C. Bronchial aery, D. Left mainstem bronchus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e., Pulmonary aery', 'role': 'assistant'}]