This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Histo Pathology, Subject name: Pathology
[{'content': 'For detection of carcinoma lip, stain used is? \nSelect and explain. \nA. Giemsa, B. Crystal violet, C. Toulidine blue, D. Hematoxylin and eosin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. (c) Toulidine blue(Ref: Early Diagnosis and Treatment of Cancer Series: Head and Neck Cancers, Wayne Koch Pg. 54)*Toluidine blue stain is used as a marker to differentiate lesions at high risk of progression in order to improve early diagnosis of oropharyngeal carcinomas.*Toluidine blue, an acidophilic metachromatic dye of thiazine group selectively stains acidic tissue components (sulfates, carboxylates and phosphate radicals), thus staining DNA and RNA.', 'role': 'assistant'}]