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
James classified habits as: 
Select and explain. 
A. Useful and Harmful., B. Intentional and Unintentional., C. Compulsive and Non-compulsive., D. None of the above.
A: Useful and Harmful.
Answer: A: Useful and Harmful. 
Explanation: None