Definitely homophonic. You can tell because there are definite chords sounding together. Polyphonic would be several independent melodies overlapping each other, and monophonic would be only a single melody sounding. There are clear harmonies, and a dead giveaway is the fact that the very beginning with just the brass even sounds something like church hymn chords, which are a classic homophonic example. Why do you ask, is it a school assignment or something?
