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
Pin retained amalgam is not used in: 
Select and explain. 
A. Where margins of restoration rest below the gingiva, B. Non vital teeth, C. Hypoplastic teeth, D. Vital teeth
C: Hypoplastic teeth
Answer: C: Hypoplastic teeth 
Explanation: None