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
All of the following predispose to gastric carcinoma except - 
Select and explain. 
A. Achlorhydria, B. 'O' blood group, C. Pernicious anaemia, D. Post gastrectomy
B: 'O' blood group
Answer: B: 'O' blood group 
Explanation: Ans. is 'b' i.e., 'O' blood group