This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitamins and Minerals, Subject name: Biochemistry
[{'content': 'Vitamin required for production of Thrombin is: \nSelect and explain. \nA. Vitamin A, B. Vitamin D, C. Vitamin K, D. Vitamin E', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Vitamin K brings about post translational modification of ceain blood clotting factors. The clotting factor -II (Prothrombin) -VII -IX -X are synthesized as inactive precursors (zymogens ) in the liver.', 'role': 'assistant'}]