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': "All of the following predispose to gastric carcinoma except \nSelect and explain. \nA. Achlorhydria, B. 'O'blood group, C. Pernicious anaemia, D. Post gastrectomy", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]