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
Discoloration and accelerated wear is seen in composite restoration, if a patient is using a toothpaste having: 
Select and explain. 
A. Stannous flouride, B. Calcium carbonate, C. Chloroform, D. Both 2 and 3
D: Both 2 and 3
Answer: D: Both 2 and 3 
Explanation: Calcium carbonate is a surface abrasive and causes wear.
Chloroform causes softening of the composite matrix and causes discoloration.