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
Which is not ketogenic? 
Select and explain. 
A. Leucine, B. Lysine, C. Methionine, D. Tryptophan
C: Methionine
Answer: C: Methionine 
Explanation: Methionine is purely glucogenic leucine is purely ketogenic others are both ketogenic & glucogenicRef: DM Vasudevan - Textbook of Biochemistry, 7th edition, page no: 27