You are answering a USMLE-style medical question. Question: A 26-year-old man presents to the office complaining of persistent epigastric pain for the past 2 months. He states that his pain is worse a few hours after he eats. His father had similar symptoms. Past medical history is insignificant. He is a non-smoker and does not drink alcohol. The vital signs include blood pressure 120/90 mm Hg, heart rate 83/min, and temperature 37.0°C (98.6°F). Physical examination is insignificant except for mild epigastric tenderness. A metabolic panel reveals the following: Serum sodium 136 mEq/L Serum potassium 4.2 mEq/L Calcium 13.2 mg/dL Bicarbonate 26 mEq/L Upper gastrointestinal endoscopy reveals multiple duodenal ulcers. Which of the following is the most likely diagnosis? Options: A) Gastroesophageal reflux disease B) Gastric adenocarcinoma, intestinal type C) VIPoma D) MEN1 Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.