id say put down caucasion b/c you are mostly persian..but id say whichever culture your name represents would be best so you can avoid issues later..if you put hispanic and ur name is some FOBED out irooni **** they may question that come interview time and ask how you are hispanic
If I remember correctly, you can only pick one category. I really don't think it matters. I don't want to start another discussion on URM and how paranoid people are about it. It sounds like you identify with both. You could legitimately put either.
You would be crazy if you didn't put hispanic...put it down...I don't think they'll ask you to prove it..I've heard of many people who don't even look hispanic put it down (1/4 I mean)