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 appliance is given at which stage: 
Select and explain. 
A. Primary dentition, B. Mixed dentition, C. Permanent dentition, D. Adulthood
B: Mixed dentition
Answer: B: Mixed dentition 
Explanation: The term myofunctional therapy was proposed by lischer. Best period for myofunctional therapy is the late mixed dentition period.