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
In centrilobular (centriacinar) emphysema, there is an abnormal, permanent enlargement of the - 
Select and explain. 
A. Respiratory bronchioles, B. Alveolar ducts, C. Small bronchi, D. Bronchioles
A: Respiratory bronchioles
Answer: A: Respiratory bronchioles 
Explanation: . Respiratory bronchioles