This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2019, Subject name: Pharmacology
[{'content': 'Which of the following is an oral direct thrombin inhibitor? \nSelect and explain. \nA. Dabigatran, B. Rivaroxaban, C. Warfarin, D. Lepirudin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ORAL: Direct thrombin inhibitor- Dabigatran, Ximelagatran Direct factor Xa inhibitors Apixaban Rivaroxaban Edoxaban Betrixaban Warfarin inhibits Epoxide Reductase thus ?Activated Vit k - ? decreased gamma carboxyglutamate residue ?functionality of factor 2,7,9,10 Lepirudin: - Parenteral Direct Thrombin Inhibitor', 'role': 'assistant'}]