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
Reid's index is - 
Select and explain. 
A. Increase in chronic bronchitis, B. Decrease in chronic bronchitis, C. Increase in bronchial asthma, D. Decrease in bronchial asthma
A: Increase in chronic bronchitis
Answer: A: Increase in chronic bronchitis 
Explanation: None