How is asthma distinguished from an airway obstruction?

A. Asthma produces wheezing during expirations; airway obstruction produces stridor during inspirations.
B. Asthma produces stridor during expirations; airway obstruction produces wheezing during inspirations.
C. Asthma produces wheezing during inspirations; airway obstruction produces stridor during expirations.
D. Asthma produces stridor during inspirations; airway obstruction produces wheezing during expirations.

Answer: A