as recognized by Citibank?

I'm planning to get their Driver's edge card for the 3% supermarket and drugstores and gas cashback rebate (I'm a college student).

i already have the mtvu card with them, and looking at my statements they clump safeway under the merchandise category and longs drugs under health care... so i am a bit confused whether I will actually receive any sort of cash back!

btw, if there is a card that offers more than 3% supermarket rebate, please recommend (I know blue cash has 5% cashback on a tier system, but an average college student does NOT spend charge more than $6500 to a credit card in a year!)