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': 'Cryptogenic organising pneumonia is characterised by all of the following except - \nSelect and explain. \nA. Migratory pulmonary opacities, B. Obstructive pattern of pulmonary function, C. Arterial hypoxemia, D. Good response to corticosteroids', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]