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
Vitamin required for production of Thrombin is: 
Select and explain. 
A. Vitamin A, B. Vitamin D, C. Vitamin K, D. Vitamin E
C: Vitamin K
Answer: C: Vitamin K 
Explanation: 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.