Which of the following is precancerous lesion

LEUKOPLAKIA OR KERATOSIS This is a localized form of epithelial hyperplasia involving upper surface of one or both vocal cords. It appears as a white plaque or way growth on the cord without affecting its mobility. It is regarded as a precancerous condition because "carcinoma in situ" frequently supervenes. Hoarseness is the common presenting symptom. Treatment is stripping of vocal cords and subjecting the tissues to histology for any malignant change. Chronic laryngeal irritants as the aetiological factors should be sought and eliminated. Ref:- Dhingra; pg num:-304