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
Serotonin is synthesized from 
Select and explain. 
A. Tryrosine, B. Alanine, C. Tryptophan, D. Glycine
C: Tryptophan
Answer: C: Tryptophan 
Explanation: Serotonin is synthesized from tryptophanRef: DM Vasudevan - Textbook of Biochemistry, 7th edition, page no: 241, fig 18.10