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: Pathology
[{'content': 'Commonest type of emphysema is \nSelect and explain. \nA. Centriacinar, B. Obstructed, C. Irregular, D. Panacinar', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Centriacinar emphysema\n\nDestruction and enlargement of the central or proximal parts of acinus with sparing of distal alveoli.\nMost common type emphysema.\nUpper lobe and apices are predominant involvement.\nCommonly seen in heavy smokers and chronic bronchitis.', 'role': 'assistant'}]