<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 56-year-old man comes to the emergency department because of progressive swelling and pain in his left calf for 1 day. He does not have shortness of breath or chest pain. He has hypertension and chronic kidney disease. Current medications include enalapril, aspirin, simvastatin, and vitamin D. His temperature is 100.4F 38C, pulse is 84min, and blood pressure is 13592 mm Hg. Physical examination shows tenderness and swelling of the left lower extremity. A venous Doppler ultrasonography shows a thrombus in the left popliteal vein. Treatment with unfractionated heparin is begun. Two days later, physical examination shows improvement of symptoms. Laboratory studies at admission and 2 days after admission show:Admission Two days after admissionHemoglobin 11.2 gdL 11.1 gdLLeukocyte count 5,500mm3 6,100mm3Platelet count 230,000mm3 170,000mm3SerumProthrombin time 12 seconds 13 secondsPartial thromboplastin time 30 seconds 55 secondsEstimated glomerular filtration rate 29 mLmin1.73 m2 28 mLmin1.73 m2Which of the following is the most appropriate next step in management?? A: Switch to enoxaparin, B: Continue unfractionated heparin, C: Switch to warfarin, D: Discontinue anticoagulation, E: Obtain serum immunoassay,  <response>: This is a question about the management of deep vein thrombosis DVT in a patient with chronic kidney disease. The patient was started on unfractionated heparin for a DVT and has shown improvement after 2 days. The lab values indicate heparin-induced thrombocytopenia is unlikely. With the patients kidney disease, switching to low molecular weight heparin enoxaparin or warfarin would not be appropriate next steps. Discontinuing anticoagulation after only 2 days would be premature. The most appropriate next step would be to continue the unfractionated heparin.B: Continue unfractionated heparin 