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
In vitamin C deficiency, post-translational modification of which amino acid is defective 
Select and explain. 
A. Lysine, B. Alanine, C. Glycine, D. Arginine
A: Lysine
Answer: A: Lysine 
Explanation: Vitamin C is required for post-translational hydroxylation of proline and lysine residue.