Regurgitation of undigested food with gurgling sounds on swallowing points to a pouch forming in the pharyngoesophageal region. Zenker diverticulum is a pulsion diverticulum that mucosa herniates through Killian’s dehiscence above the upper esophageal sphincter. Food can get trapped in this pouch, leading to regurgitation of undigested material, characteristic halitosis from bacterial growth, and audible gurgling as air and contents move in the pouch with swallowing. This makes Zenker diverticulum the best fit for the presentation. In contrast, achalasia causes progressive difficulty with swallowing both solids and liquids and often a dilated esophagus without the same localized pouch-related regurgitation or halitosis. Esophageal varices typically present with bleeding rather than regurgitation of undigested food. Pyloric stenosis presents in infancy with projectile vomiting due to gastric outlet obstruction, not an upper esophageal diverticulum.