<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 22-month-old girl is brought to the emergency department with a 24-hour history of fever, irritability, and poor feeding. The patient never experienced such an episode in the past. She met the normal developmental milestones, and her vaccination history is up-to-date. She takes no medications, currently. Her temperature is 38.9C 102.0F. An abdominal examination reveals general tenderness without organomegaly. The remainder of the physical examination shows no abnormalities. Laboratory studies show the following results:UrineBlood 1WBC 1015hpfBacteria ManyNitrite PositiveUrine culture from a midstream collection reveals 100,000 CFUmL of Escherichia coli. Which of the following interventions is the most appropriate next step in evaluation?? A: Dimercaptosuccinic acid renal scan, B: Intravenous pyelography, C: Renal and bladder ultrasonography, D: Voiding cystourethrography, E: No further testing,  <response>: This is a question about the appropriate next step in evaluating a 22-month-old girl with fever, irritability, poor feeding, and a urinary tract infection caused by Escherichia coli. The key findings are the patients age, first episode of UTI, normal development and physical exam except for abdominal tenderness, and positive urine culture showing 100,000 CFUmL E. coli. In a child this young with a first UTI, imaging studies are recommended to evaluate for vesicoureteral reflux or anatomical abnormalities that may predispose to recurrent UTIs. Renal and bladder ultrasonography is the initial imaging test of choice as it is non-invasive and does not require sedation. It can detect anatomical abnormalities like hydronephrosis. Voiding cystourethrography involves catheterization and radiation exposure to detect vesicoureteral reflux. Intravenous pyelography uses contrast and radiation to assess the urinary tract anatomy. A dimercaptosuccinic acid scan evaluates renal parenchymal involvement but is not necessary in an uncomplicated first UTI. No further testing is inappropriate in this clinical scenario.C: Renal and bladder ultrasonography 