This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Medicine
[{'content': 'Kerley B lines seen in \nSelect and explain. \nA. Pulmonary embolism, B. Pulmonary edema, C. Carcinoma bronchus, D. Lung abscess', 'role': 'user'}, {'content': "Answer: B \nExplanation: In pulmonary edema,the vascularity of the lung fields becomes more prominent,and the right and left pulmonary aeries dilate.Subsequently,interstitial edema causes thickened interlobular septa and dilated lymphatics.These are evident as horizontal lines in the costophrenic angles(septal or Kerley B lines). <reference:Davidson' s medicine-22nd edition page no:550.", 'role': 'assistant'}]