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
Which of the following is a myofunctional appliance? 
Select and explain. 
A. Catalan's appliance, B. Hawley's appliance, C. Expansion screw, D. Derichsweiler appliance.
A: Catalan's appliance
Answer: A: Catalan's appliance 
Explanation: Catalans or lower anterior inclined plane appliance is used to treat cross bites. The inclined plane has a 450 angulation, which forces the maxillary teeth in cross bite to a more labial position. It is teeth supported functional appliance. Expansion screw and Derichsweiler are expansion appliances.