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: Unknown
All are purely Glucogenic amino acids except ? 
Select and explain. 
A. Valine, B. Alanine, C. Tryptophan, D. Methionine
C: Tryptophan
Answer: C: Tryptophan 
Explanation: Ans. (c) TryptophanRef - Lippincott's 4/e, / 261.