This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chronic Obstructive Pulmonary Disease, Subject name: Medicine
Which of the following is due to chronic smoking: 
Select and explain. 
A. Centri-acinar emphysema, B. Panacinar emphysema, C. Irregular emphysema, D. Mixed variety
A: Centri-acinar emphysema
Answer: A: Centri-acinar emphysema 
Explanation: Ans. (a) Centri-acinar emphysemaRef: Harrison 18th edition, Chapter 13* Centri-acinar lesions are more common and severe in the upper lobes, particularly in the apical segments.* In severe centriacinar emphysema the distal acinus also becomes involved, and so, as noted, the differentiation from panacinar emphysema becomes difficult.* This type of emphysema is most commonly seen as a consequence of cigarette smoking in people who do not have congenital deficiency of a^antitrypsin.