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
Prophobilinogen in urine produces pink colour with which of the following reagent? 
Select and explain. 
A. Fouchet's reagent, B. Benedict's reagent, C. Sodium nitropruside, D. Ehrlich's aldehyde reagent
D: Ehrlich's aldehyde reagent
Answer: D: Ehrlich's aldehyde reagent 
Explanation: Prophobilinogen, urobilinogen and stercobilinogen reacts with Ehrlich's aldehyde reagent to form red colour. Ref: Vasudevan Biochemistry, 4th Edition, Pages 256, 493