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': 'Risk factor for carcinoma stomach are all, EXCEPT: \nSelect and explain. \nA. Blood group A, B. Postgastrectomy, C. Adenomatous polyp, D. Atrophic gastritis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Impoant quotes (Maingot's 10/e, Page 1007): In several large studies from the scandinan countries, it was found that there is no correlation between gastric cancer and blood group A. Ref: Maingot's 10/e, Page 1007.", 'role': 'assistant'}]