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
Myofunctional appliances are 
Select and explain. 
A. Active removable appliances, B. Passive appliances delivering forces from surrounding oral and periodontal tissues, C. Semi-fixed appliances, D. Fixed appliances
B: Passive appliances delivering forces from surrounding oral and periodontal tissues
Answer: B: Passive appliances delivering forces from surrounding oral and periodontal tissues 
Explanation: None