You are answering a USMLE-style medical question. Question: A 38-year-old woman presents to an urgent care clinic with the complaint of epigastric discomfort and cramping pain for the past 2 hours. She states that she has experienced similar pain in the past. These episodes occur mostly after meals and often subside several hours after she finishes eating. Due to this reason she mostly avoids eating. She says she has lost a few pounds in the last couple of months. She is a smoker and drinks alcohol occasionally. Past medical history is insignificant except for chronic knee pain, for which she takes over the counter painkillers. Her temperature is 37°C (98.6°F), respiratory rate is 16/min, pulse is 77/min, and blood pressure is 120/89 mm Hg. A physical abdominal exam is unremarkable, including examination of the abdomen. Which of the following is the most likely diagnosis? Options: A) Choledocholithiasis B) Pancreatitis C) Gastric peptic ulcer D) Gallbladder cancer Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.