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: Pathology
A 40 year old tobacco chewer was given a routine oral examination; on examination non-scrapable white patch was noticed in his left buccal mucosa.

Disease can be further evaluated by 
Select and explain. 
A. Toluidine blue solution, B. Rose Bengal stains, C. Caleoflaw white stains, D. None of the above
A: Toluidine blue solution
Answer: A: Toluidine blue solution 
Explanation: None