This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anticoagulants and Coagulants, Subject name: Pharmacology
A patient of thrombosis of veins has been receiving coumarin therapy for three years. Recently she developed bleeding tendency. How will you reverse the effect of coumarin therapy? 
Select and explain. 
A. Protamine injection, B. Vit K injection, C. Infusion of fibrinogen, D. Whole blood transfusion
B: Vit K injection
Answer: B: Vit K injection 
Explanation: Ans. (B) Vit. K injection(Ref: KDT 8/e p661,662)Vitamin K is used to reverse bleeding tendency (raised INR) in warfarin overdose whereas fresh frozen plasma is treatment of choice for bleeding due to warfarin.