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
Commonest type of emphysema is 
Select and explain. 
A. Centriacinar, B. Obstructed, C. Irregular, D. Panacinar
A: Centriacinar
Answer: A: Centriacinar 
Explanation: Centriacinar emphysema

Destruction and enlargement of the central or proximal parts of acinus with sparing of distal alveoli.
Most common type emphysema.
Upper lobe and apices are predominant involvement.
Commonly seen in heavy smokers and chronic bronchitis.