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': 'Pit and fissure sealants are bound to tooth surface by \nSelect and explain. \nA. Chemical bond, B. Mechanical Retention, C. Adhesive bond, D. Chemical and mechanical bond', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]