<prompt> Which of the following represents the best method in diagnosing medullary cystic disease of the kidney?UltrasoundNuclear scanUrographyBiopsy  <response>: Kidney biopsy is the gold standard for diagnosis of renal diseases. Kidney biopsy of the coex in medullary cystic disease shows secondary glomerulosclerosis. Ref: Genetic Diseases of the Kidney By Richard P. Lifton, Page 456 ; Radiological Imaging of the Kidney By Emilio Quaia, Pages 299-300 