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
The agent used to stain soft tissues is called 
Select and explain. 
A. Staining agent, B. Disclosing agent, C. Mordent, D. All
B: Disclosing agent
Answer: B: Disclosing agent 
Explanation: None