<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:Five days after undergoing an open colectomy and temporary colostomy for colon cancer, a 73-year-old man develops severe pain and swelling of the left calf. He was diagnosed with colon cancer 3 months ago. He has hypothyroidism and hypertension. His father died of colon cancer at the age of 68. He does not smoke. Prior to admission, his medications included levothyroxine, amlodipine, and carvedilol. Since the surgery, he has also been receiving unfractionated heparin, morphine, and piperacillin-tazobactam. He is 172 cm 5 ft 8 in tall and weighs 101 kg 223 lb; BMI is 34.1 kgm2. He appears uncomfortable. His temperature is 38.1C 100.6F, pulse is 103min, and blood pressure is 12892 mm Hg. Examination shows multiple necrotic lesions over bilateral thighs. The left calf is erythematous, tender, and swollen. Dorsiflexion of the left foot elicits pain behind the knee. The abdomen is soft and nontender. There is a healing midline incision and the colostomy is healthy and functioning. The remainder of the examination shows no abnormalities. Laboratory studies show:Hemoglobin 13.6 gdLLeukocyte count 12,100mm3Platelet count 78,000mm3Prothrombin time 18 seconds INR 1.1Activated partial thromboplastin time 46 secondsSerumNa 138 mEqLCl- 103 mEqLK 4.1 mEqLUrea nitrogen 18 mgdLGlucose 101 mgdLCreatinine 1.1 mgdLWhich of the following is the most appropriate next step in management?? A: Switch from unfractionated heparin to warfarin therapy, B: Switch from unfractionated heparin to argatroban therapy, C: Administer vitamin K, D: Transfuse platelet concentrate, E: Administer fresh frozen plasman,  <response>: This is a question about a 73-year-old man who recently underwent colectomy and colostomy for colon cancer and now has severe pain and swelling in his left calf. The key findings are:- 5 days post-op from colectomy and colostomy - Severe left calf pain and swelling- Fever, tachycardia, normal BP- Necrotic skin lesions on thighs- Left calf is erythematous, tender, swollen- Pain with dorsiflexion of left foot- Receiving heparin, morphine, antibiotics post-op- Mildly elevated PT and markedly elevated PTT- Mild thrombocytopenia The clinical picture is most consistent with heparin-induced thrombocytopenia HIT complicated by venous thromboembolism involving the left lower extremity. HIT occurs in about 3 of patients receiving heparin and causes thrombocytopenia due to an immune-mediated reaction. The markedly elevated PTT supports the diagnosis. The priority is to stop the heparin, as it can worsen thrombosis in HIT. Fresh frozen plasma or vitamin K are not indicated. Platelet transfusion is not usually recommended in HIT as it can worsen thrombosis. Argatroban would be a reasonable alternative anticoagulant to heparin in this patient with HIT.B: Switch from unfractionated heparin to argatroban therapy 