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
Precursor of melanin is: 
Select and explain. 
A. Phenylalanine, B. Tryptophan, C. Tyrosine, D. Methionine
C: Tyrosine
Answer: C: Tyrosine 
Explanation: None