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': 'Coils are incorporated in orthodontic appliances to: \nSelect and explain. \nA. Decrease the amount of force, B. Increase the range of movement, C. Increase flexibility, D. Increase the amount of force', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]