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: Microbiology
[{'content': 'H. pylori is found in: \nSelect and explain. \nA. Epithelium, B. Mucosa, C. Muscularis mucosa, D. Adventitia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Mucosa', 'role': 'assistant'}]