Final answer:
The next step in a patient with GERD symptoms and alarm symptoms, including food stuck in the chest, would be upper endoscopy.
Step-by-step explanation:
The next step in a patient with GERD symptoms and alarm symptoms, including food stuck in the chest, would be option C) Upper endoscopy. Upper endoscopy is a diagnostic procedure that allows direct visualization of the esophagus, stomach, and duodenum to identify any potential abnormalities or causes of the symptoms. It can help determine if there are any structural issues, such as strictures or esophageal ulcers, that may require further intervention.