Is "the" a noun, adjective, adverb, or verb?

Adverb

Explanation:

An adverb is  a word belonging to one of the major form classes in any of numerous languages, typically serving as a modifier of a verb, an adjective, another adverb, a preposition, a phrase, a clause, or a sentence, expressing some relation of manner or quality, place, time, degree, number, cause, opposition, affirmation, or denial, and in English also serving to connect and to express comment on clause content

it can be be a noun and a adjective