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
Combination that can be used for restoring the missing teeth are: 
Select and explain. 
A. Porcelain opposing porcelain, B. Acrylic opposing acrylic, C. Porcelain opposing teeth with gold veneering, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: All given options are valid restorative options for restoring a missing tooth.