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
Creatinine is formed from : 
Select and explain. 
A. Arginine, B. Lysine, C. Leucine, D. Histamine
A: Arginine
Answer: A: Arginine 
Explanation: Glycine, arginine and methionine all paicipate in creatine biosynthesis