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': 'Which of the can following myofunctional appliance be used in uncooperative patients with class II malocclusions? \nSelect and explain. \nA. Activator, B. Frankel II, C. Bionator, D. Herbst', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Indications for Herbst appliance: \n\nCorrection of class II due to retrognathic mandible.\nAs an anterior repositioning splint, in patients having TMJ disorders.\nCan be used in mouth breathers.\nIt is fixed, so can be used in uncooperative patients.', 'role': 'assistant'}]