Commercial use of a music created thanks to MuseScore Sounds !!!

Hello.

I have a important question.
I wanted to know if it was legal or not to export a composition with MuseScore's sheet music using MuseScore sounds (or soundfront [the basic one]) into .WAV and then sell this new file as it was an original work but using a soundfront that musn't be...
Maybe MuseScore sounds themselves are copyrighted, and there commercial use is illegale... Or, maybe they are free to be used this way (not alone but organised in an original musical track)...
But I don't know and I need your help. It's for a project !

I will be glad if you answer me about it.