This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Medicine
Cough and sputum in COPD are primarily due to changes in 
Select and explain. 
A. Large airways, B. Medium airways, C. Small airways, D. Lung parenchyma
A: Large airways
Answer: A: Large airways 
Explanation: Large airways- Cigarette smoking often results in mucus gland enlargement and goblet cell hyperplasia, leading to cough and mucus production that define chronic bronchitis, but these abnormalities are not related to airflow limitation.Small airways- The major site of increased resistance in most individuals with COPD is in airways <=2 mm diameter.Lung parenchyma- Emphysema is characterized by destruction of gas-exchanging air spaces, i.e., the respiratory bronchioles, alveolar ducts, and alveoli.Ref: Harrison 19e pg: 1701