Shaswat, A67-year-old male comes to the physician's office complaining of severe pain in the right foot with paleness of right toe. The patient had a history of receiving unfractionated heparin 7 days back. The hemogram of the patient is as shown below: Hb 13.2 g/dL WBC 10000/mm3 Platelet 50000/mm3 Which of the following should be used to treat this condition?