A is the correct answer. Why?

Explanation

Dabigatran is a direct oral anticoagulant (DOAC) that functions as a direct thrombin inhibitor, which prevents the conversion of fibrinogen to fibrin in the coagulation cascade. Other DOACs include rivaroxaban and apixaban. Dabigatran is commonly used to reduce the risk of recurrent venous thromboembolism, cerebral vascular accident, and systemic embolism in nonvalvular atrial fibrillation. Anticoagulation can cause life-threatening complications, such as intracranial hemorrhage, as seen in this patient with a traumatic subarachnoid hemorrhage. Given the life-threatening nature of this bleed, emergent reversal of dabigatran with idarucizumab, a monoclonal antibody fragment that binds dabigatran, is indicated. If reversal is needed, but idarucizumab is not available, hemodialysis is effective at removing dabigatran within 2 hours. If idarucizumab is not available, reversal with prothrombin complex concentrate may be effective.

Protamine sulfate (B) is indicated for heparin reversal. Prothrombin complex concentrate (C), also known as factor IX complex, is the reversal agent for warfarin and other vitamin K antagonist anticoagulants. It may be used if idarucizumab is not available but it is not the treatment of choice. Vitamin K (D) can be used for nonemergent warfarin reversal, such as a supratherapeutic INR in the absence of active bleeding.