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: Dental
[{'content': 'Periodontal pockets which offer the least possibility for\nbone regeneration are classified as\t________ pockets. \nSelect and explain. \nA. suprabony, B. one-wall infrabony, C. two-wall infrabony, D. three-wall infrabony', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]