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': 'Myofunctional appliances are \nSelect and explain. \nA. Active removable appliances, B. Passive appliances delivering forces from surrounding oral and periodontal tissues, C. Semi-fixed appliances, D. Fixed appliances', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]