This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Radiology
[{'content': 'Earliest radiological sign of pulmonary venous hypeension in chest X-ray is - \nSelect and explain. \nA. Cephalization of pulmonary vascularity, B. Pleural effusion, C. Kerley B lines, D. Alveolar pulmonary edema', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Upper lobe venous diversion is the 1st radiological sign of PVH. Kerley B lines , perihilar haze ,peribronchial cuffing,pulmonary ossicles,fine punctate calcification and perihilar wing pattern.', 'role': 'assistant'}]