This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
[{'content': 'Which vitamin required for hydroxylation of proline? \nSelect and explain. \nA. A, B. D, C. C, D. K', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Vitamin-c is required for hydroxylation of proline and lysine They form cross links and maintain stability of collagen Ref:Guyton and Hall textbook of medical physiology 12th edition,page number:229', 'role': 'assistant'}]