Is this fine to answer WSL solution for a Windows10 related question which can be resolve using WSL in Windows 10?
There isn't anything technically wrong with doing so, but keep in mind that providing a WSL answer is similar to telling them to install Cygwin. It's a relatively large change to the system that should only be performed if necessary - otherwise a more native solution is preferred.
Note that before 1709 WSL was considered a dev-only/beta feature. Post-1709 it has graduated to a full feature, so this is less of an issue.
The bottom line is, if you have an answer that depends on WSL but still answers the question, go ahead and post it. It's better than nothing, and might even be preferred if they already have WSL installed. But if you also have a native answer, it's good if you can post that too :)