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
Which of the following enters the TCA cycle at succinyl CoA step 
Select and explain. 
A. Tryptophan, B. Tyrosine, C. Glycine, D. Methionine
D: Methionine
Answer: D: Methionine 
Explanation: Amino acids that enter at succinyl CoA step are:
	
Valine
Isoleucine
Methionine
Threonine.