Benedict's Test for Reducing Sugars Steps:

• Benedict's solution detects reducing sugars by color change upon heating.
• No change (blue) indicates absence; green/yellow shows low concentration; orange/red shows high.
• Yellow color confirms reducing sugars are present, though at low levels.
• Milk contains lactose, a reducing sugar, consistent with this result.

Why C is correct:

• Yellow precipitate in Benedict's test directly indicates the presence of reducing sugars, as the reagent reduces to form colored cuprous oxide.

Why the others are wrong:

• A: Yellow color proves reducing sugars are present, not absent.
• B: Yellow indicates low (not high) concentration; test is not specific to fructose.
• D: Sucrose is non-reducing and undetectable by Benedict's; color unrelated to its concentration.

Final answer: C