Which of the following is precancerous lesion -
Lichen planus has no malignant potential.

Papilloma– “The malignant transformation from benign non keratining squamous papilloma to squamous cell carcinoma can occur in children, but is rarely seen” 
Leukoplakia is a white patch, in which there is epithelial hyperplasia along with atypical cells. It is a premalignant condition. Another name for leukoplakia is hyperkeratosis dyskeratosis
Smoking is a predisposing factor, not a premalignant condition. y In some cases of chronic laryngitis, the laryngeal mucosa becomes dysplastic particularly over true vocal folds and is a premalignant condition.
Chronic inflammatory conditions of larynx like chronic laryngitis may develop into malignancy.

Keratosis of larynx/leukoplakia:- 
It is epithelial hyperplasia of the upper surface of one or both vocal cords.

Appears as a white plaque or warty growth on cord without affecting its mobility
Regarded as a precarcerous condition as Ca in situ develops frequently
T/t = stripping of cords
Pachydermia of larynx
Laryngitis sicca
Keratosis of larynx
Scleroma larynx