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
Which Branched-chain amino acid is purely ketogenic- 
Select and explain. 
A. Lysine, B. Leucine, C. Isoleucine, D. Valine
B: Leucine
Answer: B: Leucine 
Explanation: Ans. is 'b' i.e., Leucine o Branched-chain amino acids are leucine, Isoleucine, and Valine. Leucine is purely ketogenic. Isoleucine is both ketogenic and glucogenic. Valine is glucogenic.