A Proton-Pump inhibitor is used to treat Gastroesophageal Reflux, which of the following medications would be used?

A. Spironolactone: Spironolactone is a diuretic, not a proton-pump inhibitor. B. Albuterol: Albuterol is a bronchodilator used for respiratory conditions, not GERD. C. Heparin: Heparin is an anticoagulant, unrelated to GERD treatment. D. Omeprazole (Prilosec): Omeprazole is a proton-pump inhibitor that reduces gastric acid production, commonly used in GERD.