If music is used for a live-performance (i.e. theatre, stand-up, or award shows) licenses can easily be purchased from the product page for a small amount. Also counts for "all" other content where proper attribution is not possible.
If music is used for a project online where you can easily give credit/attribution (i.e. YouTube-videos, animation, playlists)
you can download the music for free with a CC-license.
If proper credit is not possible - use "License #1".