This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Which of the following do not form violet colour in Biuret test? 
Select and explain. 
A. Dipeptides, B. Alanine, C. Lactose, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Biuret test is for proteins. This test requires minimum of two peptide bonds.