<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 23-year-old woman presents with fever, chills, nausea, and urinary urgency and frequency. She says that her symptoms began 4 days ago and have progressively worsened. Her past medical history is significant for a 6-month history of recurrent urinary tract infections UTIs. Her vital signs include: temperature 39.0C 102.2F, blood pressure 10070 mm Hg, pulse 92min, and respiratory rate 25min. On physical examination, there is moderate left costovertebral angle tenderness. Laboratory findings are significant for the following:WBC 8,500mm3RBC 4.20 x 106mm3Hematocrit 41.5Hemoglobin 13.0 gdLPlatelet count 225,000mm3UrinalysisColor Dark yellowClarity TurbidpH 6.5Specific gravity 1.026Glucose NoneKetones NoneNitrites PositiveLeukocyte esterase PositiveBilirubin NegativeUrobilirubin 0.6 mgdLProtein TraceBlood NoneWBC 25hpfBacteria ManyWhich of the following is the most likely diagnosis in this patient?? A: Pyelonephritis, B: Uncomplicated cystitis, C: Complicated cystitis, D: UTI, E: Acute obstructing nephrolithiasis,  <response>: Based on the information provided in the question stem, this patient is a 23-year-old woman with fever, chills, nausea, urinary urgency and frequency that started 4 days ago and have progressively worsened. She has a history of recurrent UTIs in the past 6 months. Her vital signs show fever, tachycardia and tachypnea. Physical exam reveals costovertebral angle tenderness. Lab findings show leukocytosis, microscopic hematuria, pyuria, positive nitrites and bacteria. This presentation is most consistent with pyelonephritis given the systemic symptoms fever, chills, nausea, costovertebral angle tenderness and laboratory evidence of infection leukocytosis, pyuria, bacteria. Pyelonephritis refers to infection of the renal pelvis and parenchyma, while cystitis refers to infection limited to the bladder. The recurrent nature also makes this more likely an upper tract infection. Nephrolithiasis would not explain the constitutional symptoms.A: Pyelonephritis 