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
Oral screen: 
Select and explain. 
A. Causes the child to breathe through the nose, B. Allows for the passage of air through mouth, C. Prevents passage of air through nares, D. Allows the passage of air through mouth and nose
A: Causes the child to breathe through the nose
Answer: A: Causes the child to breathe through the nose 
Explanation: The oral screen like structure enveloping the teeth buccally/ labially help in treating the mouth breathing or thumb sucking habits. This allows for the child to shift from oral to nasal breathing, which in turn allows the nasal passages to develop and the palate to descend.
Reference: Textbook of orthodontics, 2nd ed Gurkeerat Singh page no 574