This isn't a license thing, this is a copyright thing. It is perfectly fine to quote any copyrighted work as long as
the quote is reasonably small, as determined by the context for which the quote is used
the quote is used as part of a larger work (here: answer)
the quote is subject to commentary from the surrounding text, or is used to illustrate/clarify some subject matter
the quote is not modified (unless such modifications are marked as per common custom)
the source is properly attributed.
The specific conditions for citations depend on your jurisdiction.
In the US, this would be part of fair use.
In my jurisdiction (Germany) there is an explicit right to cite.
In the Netherlands, there is also an explicit citaatrecht for scientific works or similar works, which would seem apply to a Stack Exchange answer as well.