<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 17-year-old adolescent male is brought to the emergency department by fire and rescue after being struck by a moving vehicle. The patient reports that he was running through his neighborhood when a car struck him while turning right on a red light. He denies any loss of consciousness. His temperature is 99.0F 37.2C, blood pressure is 8856 mmHg, pulse is 121min, respirations are 12min, and SpO2 is 95 on room air. The patient is alert and oriented to person, place and time and is complaining of pain in his abdomen. He has lacerations on his face and extremities. On cardiac exam, he is tachycardic with normal S1 and S2. His lungs are clear to auscultation bilaterally, and his abdomen is soft but diffusely tender to palpation. The patient tenses his abdomen when an abdominal exam is performed. Bowel sounds are present, and he is moving all 4 extremities spontaneously. His skin is cool with delayed capillary refill. After the primary survey, 2 large-bore IVs are placed, and the patient is given a bolus of 2 liters of normal saline.Which of the following is the best next step in management?? A: Abdominal CT, B: Focused Abdominal Sonography for Trauma FAST exam, C: Diagnostic peritoneal lavage, D: Diagnostic laparoscopy, E: Emergency laparotomy,  <response>: This is a question about the initial management of a 17-year-old male who was struck by a vehicle and is now in the emergency department with abdominal pain and tenderness. The key findings are that he was in a traumatic accident, is hemodynamically unstable with hypotension and tachycardia, has abdominal tenderness on exam, and has already received initial resuscitation with IV fluids. The question is asking for the best next step in management. Based on the patients presentation, there is concern for intra-abdominal injury that requires further evaluation. However, he is unstable so the next test should be rapid, non-invasive, and able to quickly identify any intra-abdominal bleeding or organ injury that may require emergent operative management.Choice A, abdominal CT scan, provides excellent anatomical detail but can take time to perform and interpret. Choices C and D, diagnostic peritoneal lavage and diagnostic laparoscopy, are more invasive procedures. Choice E, emergency laparotomy, is premature without further evaluation. Choice B, FAST exam, is rapid, noninvasive, and can quickly identify free fluid in the abdomen indicating likely intra-abdominal injury. This would be the best next step to quickly assess for bleeding or organ damage in this unstable trauma patient.B: Focused Abdominal Sonography for Trauma FAST exam 