This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
All are true about warfarin except: 
Select and explain. 
A. Act through inhibition of coagulation factor IX, B. Protamine sulphate reverses its action, C. Monitoring is done through INR, D. Target of INR with warfarin is generally 2-3
B: Protamine sulphate reverses its action
Answer: B: Protamine sulphate reverses its action 
Explanation: Ans: b. Protamine sulphate reverses its action.Warfarin induced skin necrosis is a rare complication characterized by the appearance of skin lesion 3-10 days after initiation of treatment.Dose of warfarin adjusted to give an INR of 2-4, the precise target depending on the clinical situation.The reference range for prothrombin time is usually around 12-13 seconds and the INn in absence of anticoagulation therapy is 0. 8-1. 2Warfarin: Dose regulation is done by prothrombin time & INR (Heparin/aPTT/clotting time.Antagonist is Vit K (c. f Heparin- Protamine sulphate).