Identify the nature of the sugars

• Glucose is an aldohexose (contains an aldehyde group in its open-chain form).
• Fructose is a ketohexose (contains a ketone group in its open-chain form).

So, a test that distinguishes aldoses from ketoses will distinguish glucose from fructose.

Check each option

A) Barfoed's test

• Barfoed's test is mainly used to distinguish monosaccharides from disaccharides.
• Both glucose and fructose are monosaccharides.
• Hence, this test does not distinguish them.

B) Fehling's test

• Fehling's solution is reduced by reducing sugars.
• Glucose is a reducing sugar.
• Fructose also gives a positive Fehling's test in alkaline medium due to enediol rearrangement.
• Hence, this test does not distinguish them.

C) Seliwanoff's test

• Seliwanoff's test distinguishes ketoses from aldoses.
• Fructose (ketose) gives a rapid cherry-red color.
• Glucose (aldose) reacts much more slowly and does not give the same immediate result.
• Therefore, this test does distinguish fructose from glucose.

D) Benedict's test

• Benedict's test also detects reducing sugars.
• Both glucose and fructose respond positively.
• Hence, it does not distinguish them.

Conclusion

The correct test to distinguish fructose from glucose is: $\boxed{\text{Seliwanoff's test}}$

Comparison with stored correct answer

• Derived answer: C
• Stored correct answer: C
• They match.