A 70-year-old woman underwent an open AAA repair 3 days ago. She has had rising creatinine over the past two days, which has now reached 3.2 mg/dL, but continues to have urine output. Which of the following test results is MOST consistent with acute tubular necrosis as an etiology of her renal failure?

A) Creatinine > 3 mg/dL
B) Creatinine > 5 mg/dL
C) Fractional excretion of sodium >2%
D) Fractional excretion of sodium <1%