This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of protein and amino acid, Subject name: Biochemistry
"Indican" is a metabolite of 
Select and explain. 
A. Histidine, B. Tryptophan, C. Tyrosine, D. Valine
B: Tryptophan
Answer: B: Tryptophan 
Explanation: Indian is a major excretory product in the metabolism of tryptophanRef: DM Vasudevan - Textbook of Biochemistry, 7th edition, page no: 242, fig 18.11