This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
A patient is found to have a duodenal ulcer by upper endoscopy. The likelihood of this patient having H. pylori in the gastric antrum is? 
Select and explain. 
A. 5%, B. 20%, C. 60%, D. 95%
C: 60%
Answer: C: 60% 
Explanation: .