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 amino acid is excreted in urine in maple syrup urine disease 
Select and explain. 
A. Tryptophan, B. Phenylalanine, C. Leucine, D. Arginine
C: Leucine
Answer: C: Leucine 
Explanation: In maple syrup urine disease there is the excretion of branched chain amino acids (isoleucine, leucine, valine) and their keto acids (α -keto β-methyl valerate, α-ketoisocaproate, α-ketoisovalerate) in the urine.