Select every form that can fill the gap: "The caretaker has ____ the lamps in the hallway."
Explication
After has the sentence needs a past participle, and this verb has two that are both current. Lit is the usual choice in a verbal sentence such as this one, while lighted is equally standard and turns up most often before a noun, as in a lighted window; American English keeps both as well. Lighting is the -ing form that follows be, and lighten is a separate verb meaning to make something brighter.