<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 37-year-old man presents to the emergency department for a persistent fever. The patient states he has felt unwell for the past week and has felt subjectively febrile. The patient has a past medical history of a suicide attempt and alcohol abuse. He is not currently taking any medications. The patient admits to using heroin and cocaine and drinking 5-8 alcoholic drinks per day. His temperature is 103F 39.4C, blood pressure is 9259 mmHg, pulse is 110min, respirations are 20min, and oxygen saturation is 96 on room air. Cardiopulmonary exam is notable for a systolic murmur heard best along the left sternal border. Dermatologic exam reveals scarring in the antecubital fossa. Which of the following is the next best step in management?? A: Blood cultures, B: Chest radiograph, C: CT scan, D: Ultrasound, E: Vancomycin and gentamicin,  <response>: This is a question about a patient with fever who has a history of IV drug use and alcohol abuse. The key findings are fever, murmur, and track marks. The main diagnostic considerations are infective endocarditis, pneumonia, and sepsis. Blood cultures are needed to identify any bacteremia and target antibiotic therapy. Chest x-ray can evaluate for pneumonia. CT scan is not indicated at this point. Ultrasound of the heart could evaluate for endocarditis but blood cultures are more important initially. Starting empiric antibiotics is premature before diagnostic evaluation.A: Blood cultures 