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
A helix is placed for: 
Select and explain. 
A. Activation, B. Increasing the flexibility and range, C. Esthetics, D. Retention
B: Increasing the flexibility and range
Answer: B: Increasing the flexibility and range 
Explanation: None