Epimer combination (s) is/are
When sugars are different from one another, only in configuration with regard to a single carbon atom, other than reference carbon atom, they are called epimers\Ref: DM Vasudevan, 7th edition, page no: 71
D-glucose & D-fructose
D-mannose & D-talose
D-glucose & D-mannose
D-glucose & D-gulose
Metabolism of carbohydrate