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': 'Smoking is generally not associated as a risk factor with - \nSelect and explain. \nA. Small cell carcinoma, B. Respiratory bronchiolitis, C. Emphysema, D. Bronchiolitis obliterans organizing pneumonia', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]