This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Stomach & Duodenum, Subject name: Surgery
[{'content': 'A previously healthy florist presents to the emergency department after vomiting blood in his flower shop. While waiting to be seen he has another episode of hematemesis. What is the most likely cause of his bleeding? \nSelect and explain. \nA. Peptic ulcer disease (stomach or duodenum), B. Hiatal hernia, C. Mallory-Weiss tear, D. Gastric carcinoma', 'role': 'user'}, {'content': "Answer: A \nExplanation: Peptic ulcer disease is the most common cause of UGI bleeding in patients presenting to the emergency department. Most bleeding ulcers (80%) will stop with conservative measures. A visible vessel seen during endoscopy can have up to a 55% chance of rebleeding. Other causes of bleeding include gastritis, gastric cancer, esophagitis, Mallory-Weiss tear, Dieulafoy's lesion, and esophageal varices, but these occur less commonly than peptic ulcer as a likely cause of bleeding.", 'role': 'assistant'}]