Are some combinations of the custom licence options incompatible?
Yes. There is one combination of options that does not make sense: No Derivative Works combined with Share Alike. This combination does not work because the Share Alike condition applies only to derivative works. If you choose both options, we will give you a friendly reminder about this and ask that you please make your selection again. Note that every CC licence requires licensees to attach the original licence terms to every verbatim copy they distribute. So if you copy a music file licensed under a non-commercial licence, you must tell the world that your copy of that file is also licensed under a non-commercial licence. The Share Alike option simply extends this requirement to all derivative works as well. So if you were to use that same non-commercial MP3 in a documentary film, the Share Alike provision would oblige you to license your film under a non-commercial licence, too.
