A 10 year old has diffuse bilateral white areas on the buccal mucosa, dorsum of the tongue and the floor of the mouth. The mother tells the dentist that she has noticed this appearance for at least 3 years, but she was not concerned since she has had a similar condition all of her life. The most likely diagnosis is

white sponge nevus.

leukoplakia.

frictional keratosis.

allergic reaction to cinnamon.