<prompt> The earliest markers of renal injury in lead poisoning is the:-Elevated lead level in urineElevated free protoporphyrin in urineElevated b 2 microglobulin in urineElevated coproporphyrin in urine  <response>: Elevated urinary levels of N-acetyl-3-D-glucosaminidase and b-2-microglobulin may serve as early markers of renal injury. 