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: Microbiology
Stain for premalignant lesions 
Select and explain. 
A. Toluidine blue, B. Malachite green, C. Potassium iodide, D. Iodine
A: Toluidine blue
Answer: A: Toluidine blue 
Explanation: Toluidine blue is the stain for premalignant lesions.