I guess you mean the case ending on "Ona"?
"Göre" means "according to" and we use dative case on the subject that has the opinion. Ona göre; Bana göre; Duo'a göre etc. So the sentence is literally "According to her/him, those are all very good", but the standard answer uses more common wording: "In his/her opinion". (Maybe this had you expecting genitive case?)
If I did not answer your question, feel free to be more specific :-)