3. Relationship between the given molecules

• D-glucose and L-glucose - Both are enantiomers of each

other.

• D-glucose and D-galactose-Both are diastereomers of each

other. And also, the difference between these two is found

in C4 carbon so these two are epimers of each other.

• L-glucose and L-fructose- Both are constitutional isomers of

each other.