Respuesta :
it's a noun. "score" is another unit of measurement, much like "years" -- and "years" is a noun as well.
The italicized word given in the sentence above is the word "Score" and the part of speech that this word belongs is a noun. A noun is any word that serves as a name of a thing, person, animal, event, place, etc. In this case, this word is used as a noun and is described by an adjective "four". Hope this answers your question.