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
Which of the following is an example of a composite material: 
Select and explain. 
A. A filled resin, B. Colloidal silica, C. gold alloy, D. wax
A: A filled resin
Answer: A: A filled resin 
Explanation: None