Biuret test is not given by

The Biuret test is a qualitative test for compounds that contain two or more $$-CO-NH-$$ (peptide) linkages placed close to each other.
• Reagent used: alkaline $$CuSO_4$$ solution (called Biuret reagent).
• Positive test: formation of a violet-purple complex with $$Cu^{2+}$$ ions.

Let us check each option:

Option A (carbohydrates)
Carbohydrates possess only hydroxyl ($$-OH$$) and carbonyl ($$-C\! = \!O$$) groups; they have no peptide linkages. Therefore they do not complex with $$Cu^{2+}$$ in alkaline medium and give NO violet colour ⇒ Biuret test negative.

Option B (polypeptides)
Polypeptides are chains of amino-acid residues joined by many peptide bonds, so they give a strong positive Biuret test (violet colour).

Option C (urea)
Two molecules of urea condense on gentle heating to form “biuret”, which contains two $$-CO-NH-$$ groups. Hence even urea solution, after slight warming with alkali, responds positively (violet colour).

Option D (proteins)
Proteins are long polypeptide chains with numerous peptide bonds, so they also give a pronounced violet colour in the Biuret test.

Only carbohydrates lack the required peptide linkage and therefore fail to give the Biuret test.

Option A which is: carbohydrates