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
NORWEGIAN APPLIANCE is? 
Select and explain. 
A. Bionator, B. Activator, C. Frankel, D. Twin block
B: Activator
Answer: B: Activator 
Explanation: Other names of activator

Norwegian appliance
Functional jaw orthopedics.