Which one of the following conditions is considered to be definitely precancerous in the larynx?

(c) Leukoplakia(Ref. Cummings, 6th ed., 1609)Rest are not precancerous.Subglottic hemangiomas are benign vascular tumours. They are rare as such but can lead to progressive stridor. They are commonly associated with cutaneous hemangiomas (the most common benign skin vascular tumours in children). Most subglottic hemangiomas spontaneously resolve by 5 years of age. If large and progressive they can be excised by CO2 LASER or surgically.