Epimer combination (s) is/are :
C, i.e. D-glucose - Carbohydrate isomers that differ in configuration around only one carbon atom are called epimers. D-glucose and Dmannose are C2 epimers whereas D- glucose and D- galactose differ only at C4. However, D-mannose & D- galactose are not epimersQ as they differ at 2 carbons (2 & 4). Enantiomers (optical isomers or stereoisomers) are pairs of structures that are mirror images of each other but not identical , similar to left and right hand which are the same but opposite. These are non super imposable and are designated as D and L-sugar. Each enantiomer often shows different chemical reactions with other enantiomers. Because of presence of many enantiomers in living beings, there is usually a marked difference in effects of two stereoisomers. For example only one of drug stereoisomer produces desired effect while the other does not.
D-glucose & D-fructose
D-mannose & D-talose
D-glucose & D-mannose
None of these