Epimers differ at any chiral center, anomers differ at the anomeric carbon accurately describes the key difference, similarity, or comparative feature asked about in this question. In Carbohydrates, the ability to compare and contrast related concepts is essential for deeper understanding. The distinguishing feature described by Epimers differ at any chiral center, anomers differ at the anomeric carbon reflects fundamental differences in structure, function, mechanism, or origin between the compared entities. The other options (Epimers only occur in ketoses, anomers in aldoses, Anomers have di
Ref:
Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7