I sent you how to do it legitimately, not over thinking it like the rest of the people.
All you have to do is link the creator of the music in the description. Also, I would recommend putting this statement in all of your videos also.
"No copyright infringement intended. For promotional purposes only. Including Fullscreen2, Collab, Jukin Media Copyright Management. If you have any issues with ownership of the videos or any copyright; please contact me."
Bingo, you're golden.