The six CC licenses are combinations of three binary axes: commercial use, derivatives, and share-alike

All six main Creative Commons licenses require Attribution (BY). Three additional restrictions can be applied in combinations: NC (NonCommercial — no commercial use); ND (NoDerivatives — no remixes or adaptations); SA (ShareAlike — derivatives must use the same license). These combine as: BY, BY-SA, BY-ND, BY-NC, BY-NC-SA, BY-NC-ND. ND and SA are mutually exclusive (ND disallows derivatives, so SA cannot apply). Understanding the axes, not the six names by heart, is the key insight: given BY + NC + SA, you can reconstruct BY-NC-SA. Syncing a track to video counts as creating a derivative work — relevant for any ND license.

Examples

BY: most permissive, allows commercial remixes. BY-ND: redistribution only, unchanged, commercial OK. BY-NC-SA: non-commercial remixes, derivatives must use same license. BY-NC-ND: download and share only, unchanged, non-commercial only.

Assessment

You want to allow remixing but only by people who will release their remixes freely. Which CC license fits? You want to allow any use but not remixing. Which fits? Explain why ND and SA cannot be combined.