<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 75-year-old man comes to the physician because of fatigue and decreased urine output for 1 week. He takes ibuprofen as needed for lower back pain and docusate for constipation. Physical examination shows tenderness to palpation over the lumbar spine. There is pedal edema. Laboratory studies show a hemoglobin concentration of 8.7 gdL, a serum creatinine concentration of 2.3 mgdL, and a serum calcium concentration of 12.6 mgdL. Urine dipstick is negative for blood and protein. Which of the following is the most likely underlying cause of this patients symptoms?? A: Antiglomerular basement membrane antibodies, B: Immunoglobulin light chains, C: Renal deposition of AL amyloid, D: Anti double-stranded DNA antibodies, E: Hypersensitivity reaction,  <response>: Based on the information provided, this is likely a case of acute kidney injury in an older adult. The symptoms of fatigue and decreased urine output along with the physical exam finding of pedal edema and lab results showing elevated creatinine indicate impaired kidney function. The history of taking ibuprofen regularly raises suspicion for NSAID-induced nephrotoxicity as a possible cause. The normal urinalysis makes glomerular causes like anti-GBM disease or lupus nephritis less likely. The normal calcium level makes multiple myeloma less likely as a cause. Amyloidosis could cause similar findings but would likely lead to abnormal urinalysis.B: Immunoglobulin light chains 