Which of the following is not considered a symptom of bronchitis?

In the context of bronchitis, the primary symptoms typically include coughing, shortness of breath, and chest pain. These symptoms arise from the inflammation of the bronchial tubes, which can lead to irritation and difficulty breathing, among other issues.

Coughing is often the most recognizable symptom, as it reflects the body's attempt to clear mucus from the airways. Shortness of breath occurs due to narrowed air passages and inflammation. Chest pain may develop as a result of persistent coughing or the strain from inflamed airways.

Sudden weight gain is not associated with bronchitis and, therefore, is the correct choice as it does not fall within the common symptoms of this respiratory condition. Sudden weight gain could indicate various other health issues or conditions unrelated to bronchitis, such as fluid retention, changes in diet, or a side effect of medication, but it is not characteristic of bronchitis itself.