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
[{'content': "Phenylpyruvic acids in the urine is detected by: \nSelect and explain. \nA. Guthrie's test, B. VMA in urine, C. Gerhas test, D. Ferric chloride test", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ferric chloride test is a quantitative test for the detection of phenylketonuria; the addition of ferric chloride to urine give rise to a blue green colour in the presence of phenylketonuria. This colour is due to phenylpyruvate.', 'role': 'assistant'}]