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
Auto matrix is a 
Select and explain. 
A. Matrix system that automatically gets attached with retainer and the tooth, B. System where a single retainer can be used for all matrix bands, C. Retainer less matrix system designed for any tooth regardless of its circumference, D. Retainer less matrix system designed for any tooth with specific circumference
C: Retainer less matrix system designed for any tooth regardless of its circumference
Answer: C: Retainer less matrix system designed for any tooth regardless of its circumference 
Explanation: None