Which of the following is NOT a symptom of asthma?

Swollen feet are not a symptom of asthma. Asthma primarily affects the airways in the lungs, leading to respiratory issues. Common symptoms associated with asthma include difficulty breathing, chest tightness, and coughing. These symptoms arise from inflammation and narrowing of the airways, which can be triggered by various factors such as allergens or irritants.

In contrast, swollen feet can indicate a completely different medical condition, often related to issues like fluid retention or circulation problems, which are not typical manifestations of asthma. Therefore, selecting swollen feet as the answer correctly identifies it as the outlier that does not relate to asthma symptoms.