<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:Two days after undergoing emergent laparotomy with splenectomy for a grade IV splenic laceration sustained in a motor vehicle collision, a 54-year-old man develops decreased urinary output. His urine output is 350 mLday despite aggressive fluid resuscitation. During the emergent laparotomy, he required three units of packed RBCs. He has type 2 diabetes mellitus and is on an insulin sliding scale. His vital signs are within normal limits. Physical examination shows a healing surgical incision in the upper abdomen and multiple large ecchymoses of the superior right and left abdominal wall. His hematocrit is 28, platelet count is 400,000mm3, serum creatinine is 3.9 mgdL, and serum urea nitrogen concentration is 29 mgdL. Urinalysis shows brown granular casts. Which of the following is the most likely underlying cause of these findings?? A: Acute tubular necrosis, B: Rapidly progressive glomerulonephritis, C: Focal segmental glomerulosclerosis, D: Myorenal syndrome, E: Acute renal infarction,  <response>: This is a question about acute kidney injury following major surgery and trauma. The patient underwent emergent laparotomy and splenectomy after a motor vehicle collision, which required blood transfusion. He now has oliguria and rising creatinine and BUN, indicating acute kidney injury. The timeline, context of recent surgery and trauma, low hematocrit, and urinalysis findings of granular casts point towards acute tubular necrosis as the most likely cause. Rapidly progressive glomerulonephritis, focal segmental glomerulosclerosis, and renal infarction would not present this acutely after surgery. Myorenal syndrome may cause acute kidney injury after trauma but granular casts would not be expected. A: Acute tubular necrosis 