This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Basics of carbohydrate metabolism, Subject name: Biochemistry
Following are the test done for proteins, sugar & ketones. Which will be positive in starvation state in urine? 
Select and explain. 
A. 1 & 2, B. Only 2, C. Only 3, D. 2 & 3
C: Only 3
Answer: C: Only 3 
Explanation: In Starvation, Ketone body will be positive in urine. Proteins Carbohydrates Ketone bodies Biuret test positive only if it has at least 2 peptide bonds. Benedict's test Positive for reducing sugars Rothera's test (image shown below) Gerhardt's test.