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
Which of the following factors contribute to the development of duodenal ulcer 
Select and explain. 
A. 131
I, B. 125
I, C. 99
Tc, D. 32
P
A: 131
I
Answer: A: 131
I 
Explanation: None