This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: TCA Cycle, Subject name: Biochemistry
Which of the following enters the TCA cycle at succinyl-CoA step ? 
Select and explain. 
A. Histidine, B. Methionine, C. Tryptophan, D. Tyrosine
B: Methionine
Answer: B: Methionine 
Explanation: 4 amino acids enter at Succinyl-CoA step : Valine, Isoleucine, Methionine Threonine.