The term "four-part harmony" refers to music written for four voices or for some other musical mediumfour musical instruments or a single keyboard instrument, for examplewhere the various musical parts can give a different note for each chord of the music.
Does this next sentence follow, given the preceding text?
four-part harmony is very melodious to listen

Options are: [i] Yes; [ii] It's impossible to say; [iii] No;
[ii]