Which Creative Commons license should I pick?

Three quick questions usually settle it:

1. Do you want maximum reach? Pick CC0 or CC BY. Wikipedia, OpenStax, and similar projects can use only these.
2. Do you want derivatives to stay open? Add Share-Alike (SA).
3. Do you want to keep commercial rights for yourself? Add NonCommercial (NC). But know that NC excludes a lot of legitimate uses, including some non-profits.

If you're unsure, CC BY is the most-used license worldwide for a reason — credit you, do anything else they like.