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/are dentin desensitizing agent? 
Select and explain. 
A. Potassium salts, B. 33% sodium fluoride solution, C. Strontium salts, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Dentin desensitizers are materials used over open dentinal tubules on exposed root surfaces to eliminate fluid flow and desensitize dentin.