Explanation:
- Glucose and -Galactose differ in configuration of only one asymmetric carbon. So, they are called epimers.
and -Glucose differ at anomeric carbon, thus they are anomers.
(C - P) - Glucose and - Fructose are functional isomers, as they have aldehyde & ketone functional groups respectively.
(D - Q) Ribose is pentose and glucose is hexose, so they are homologous.So, the correct option is (3).