ysmr

So I got my work permit card and I went to the ssn office with the stuff I needed to get a card but I wasn't able to get it because I didn't have have the proper identification so they said I needed a state I.d and they wrote me a letter to get it at the bmv I went there and I showed them the letter and they looked at my I.d and said they wouldn't valid that are because it's under c33 category, but what does that mean? I don't understand at all. Someone please help!