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
Overcontoured tooth restoration is caused by: 
Select and explain. 
A. Underprepared tooth, B. Overprepared tooth, C. Oversized die, D. Inadequate thickness of veneer
A: Underprepared tooth
Answer: A: Underprepared tooth 
Explanation: Insuﬃcient axial reduction or under preparation of tooth leads to inevitable overcontoured restorations that hamper plaque control.