This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
All are Vitamin K dependent clotting factors 
Select and explain. 
A. Factor II, B. Protein C, C. Factor X, D. Factor IX
B: Protein C
Answer: B: Protein C 
Explanation: Vitamin K is required for the synthesis of factor 2,7,9, and 10 by the liver.Ref: Textbook of medical physiology by N Geetha, 2nd edition, page no. 107