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
Sodium nitrite is used as 
Select and explain. 
A. Antiplaque agent, B. Antirust agent, C. Desensitising agent, D. Bleaching agent
B: Antirust agent
Answer: B: Antirust agent 
Explanation: None