Specify the relationship(s) of the compounds in each of the following sets. Choose among the following terms: identical compounds, epimers, anomers, enantiomers, diastereomers, constitutional isomers, none of the above. (More than one answer may be correct.)

(a) α-D-glucopyranose and β-D-glucopyranose

(b) α-D-glucopyranose and α-D-mannopyranose

(c) b-D-mannopyranose and β-l-mannopyranose

(d) α-D-ribofuranose and α-D-ribopyranose

(e) Aldehyde form of D-glucose and α-D- glucopyranose

(f) methyl α-D-fructofuranoside and 2-O-methyl-α-D-fructofuranose