This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Which is the most common site for duodenal ulcer \nSelect and explain. \nA. Within 2 centimetres of pylorus, B. Second part of duodenum, C. Distal duodenum, D. Early part of jejunum.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: About 95 percentage of duodenal ulcers occur within 2 centimetres of the pylorus', 'role': 'assistant'}]