With that UTG rail you're pretty much limited to a LER scope or a red dot unless you have the stripper clip guide as well. If you do have the stripper clip guide, be aware that a few people, myself included, have had issues with them not being in the same plane as the forward rail so you have to run something like Burris Zee rings to be able to even get your scope on the paper without maxing out the internal adjustment in your scope. A better option mght be something like the Larue LR-608 that mounts to just your forward rail and would allow the scope to sit over the receiver.
As for rings, you can't go wrong with the ARMS22, I have the med height ones on my ARMS18 and love the setup. For scopes, like others have said, a 1-4 short dot or a 3.5-10 are winning combos. I have both a Millett DMS-1 and a Leupold Mark4 LR/T 3.5-10. Both are great but the Leupi gets more love, I need a shorty for the DMS, haha.