Which option correctly identifies a sign associated with asthma?

• A. Vasodilation of airways
• B. Elevated white blood cell count
• C. Narrowing of airway
• D. Increased muscle mass

Answer: (C)

Asthma causes obstruction by narrowing the airways due to bronchoconstriction and inflammation. This is why the sign most clearly associated with asthma is the narrowing of the airway—the airways constrict and their diameter decreases, making it harder to breathe and often producing wheezing, coughing, and chest tightness.

Vasodilation would widen airways, which isn’t the typical immediate sign of an asthma attack. An elevated white blood cell count is nonspecific and doesn’t define asthma itself, though infections can raise WBCs. Increased muscle mass can occur with long-term airway remodeling, but the immediate, defining sign of asthma is airway narrowing caused by smooth muscle constriction and inflammatory swelling.