Kenson paid $12 for two magazine was a multiple of three what are the possible prizes of the magazinez

(6,6) (8,4) (10,2) is the answeer for this question

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.

What am i doing here. add?