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
The best restoration for posterior tooth with an undermined cusp with caries is: 
Select and explain. 
A. Cast gold, B. Silver amalgam, C. Direct gold filling, D. Pin retained amalgam restoration
A: Cast gold
Answer: A: Cast gold 
Explanation: None