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': 'Oral screens are used for all the following purposes EXCEPT: \nSelect and explain. \nA. Tongue thrusting, B. Mouth breathing, C. Lip biting, D. Retraction of upper protruded teeth', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]