<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 45-year-old male with a 15-year history of diabetes mellitus presents to his primary care provider for a routine checkup. His doctor is concerned about his renal function and would like to order a test to detect renal impairment. Which of the following is the most sensitive test for detecting renal impairment in diabetic patients?? A: Cystatin C levels, B: Urine microalbumin to creatinine ratio, C: Hemoglobin A1C, D: Urine protein dipstick, E: Urinalysis,  <response>: This is a question asking about the most sensitive test for detecting renal impairment in diabetic patients. Choice C, hemoglobin A1C, tests blood sugar control over the past 3 months and does not directly assess kidney function, so it can be eliminated. Choice D, urine protein dipstick, and Choice E, urinalysis, can detect proteinuria which can indicate kidney damage, but they are not the most sensitive tests. The most sensitive tests are Choice A, cystatin C levels, and Choice B, urine microalbumin to creatinine ratio. Cystatin C is a protein filtered by the kidneys and its levels rise earlier than creatinine in kidney dysfunction. Microalbuminuria, or small amounts of albumin in the urine, is an early sign of diabetic nephropathy. Of these two sensitive tests, the urine microalbumin to creatinine ratio is likely the most sensitive for detecting early diabetic kidney disease.B: Urine microalbumin to creatinine ratio 