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
Filled sealants are better than unfilled due to: 
Select and explain. 
A. High viscosity, B. High strength, C. Cotton application, D. Low abrasion
D: Low abrasion
Answer: D: Low abrasion 
Explanation: None