You are answering a USMLE-style medical question. Question: A 45-year-old female presents to the emergency department with gross hematuria and acute, colicky flank pain. She denies any previous episodes of hematuria. She reports taking high doses of acetaminophen and aspirin over several weeks due to persistent upper back pain. The patient’s blood pressure and temperature are normal, but she is found to have proteinuria. Physical examination is negative for palpable flank masses. Which of the following is the most likely diagnosis: Options: A) Diffuse cortical necrosis B) Chronic pyelonephritis C) Papillary necrosis D) Acute Nephrolithiasis Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.