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 5-year-old residential school child walks in to your clinic with the habit of thumb sucking in association with bruxism
What would be probable cause 
Select and explain. 
A. Food habits, B. Nasal septal deviation, C. Habitual, D. Psychological
D: Psychological
Answer: D: Psychological 
Explanation: None