This question already has an answer here:
I recently encountered this question and it doesn't seem relevant for SO (maybe I'm wrong!) or any of the suggested options that flagging "this is off-topic..." suggests (SuperUser, SSCCE, SO checklist, Server Fault, recommendation), or suggesting another site (meta, superuser, tex, dba, sharepoint).
Regardless of the qualifications of the question I cited earlier, where's the option on the "suggest it moves to another site" list to choose either a StackExchange site from a drop-down, or (preferably) just click a radio button for "let moderation figure it out, but it doesn't go here!"?