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': 'Jasper jumper is a \nSelect and explain. \nA. Flexible fixed functional appliance, B. Rigid fixed functional appliance, C. Fixed functional appliance, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Herbst appliance is a rigid fixed functional appliance. Jasper jumper is a flexible fixed functional appliance.', 'role': 'assistant'}]