Which of the following medications would be prescribed most frequently to patients suffering from chronic atrial fibrillation?

Patients of chronic atrial fibrillation are at high risk of developing thromboembolism. Oral anticoagulants are most frequently advised drugs in these patients to decrease the risk of this adverse effect. Warfarin being oral anticoagulant is used as prophylaxis in chronic atrial fibrillations because of propensity of these pts. developing thromboembolism is higher.