Which of the following can be a symptom of GERD?

A persistent cough can indeed be a symptom of gastroesophageal reflux disease (GERD). This occurs because the acid from the stomach can irritate the lining of the esophagus and the throat, leading to inflammation. When this irritation occurs, it can trigger a cough reflex as the body attempts to clear the throat. Individuals with GERD may also experience other respiratory symptoms, such as hoarseness or asthma-like symptoms, due to the acid exposure impacting their airways.

The other options—frequent headaches, muscle pain, and skin rashes—are not typically associated with GERD. While headaches can be caused by many factors, they are not a direct symptom of acid reflux. Muscle pain and skin rashes also do not relate directly to the gastrointestinal issues associated with GERD, and these symptoms may stem from entirely different health conditions. Thus, the persistent cough is the clear and relevant symptom related to GERD.