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': 'Pan acinar emphysema is seen in \nSelect and explain. \nA. Smoking, B. Chronic bronchitis, C. α1 - antitrypsin deficiency, D. Spontaneous pneumothorax', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Centriancinar - Smokers, chronic bronchitis.\nPan acinar -\xa0α1 - antitrypsin deficiency.', 'role': 'assistant'}]