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
Porphobilinogen in urine produces pink colour with- 
Select and explain. 
A. Fouchet's reagent, B. Benedict's reagent, C. Sodium nitroprusside, D. Ehrlich's aldehyde reagent
D: Ehrlich's aldehyde reagent
Answer: D: Ehrlich's aldehyde reagent 
Explanation: Ehrlich's aldehyde reagent test is used for porphobilinogen and urobilinogen in urine. It is mainly used in acute intermittent porphyria.

About other options

Sodium nitroprusside (Rothera's test) → For ketone bodies
Benedict's test                                     → Glucose and other reducing sugars in urine
Fouchet's (barium sulphate) test         → Bile pigment (bilirubin)