A 54 year male, known case of type 2 diabetes for the last 13 years presents with progressive oliguria, raised serum BUN and creatinine. Her fasting plasma glucose is 234 mg/dl and HbA1c of 9.5%. Her ultrasound abdomen revealed bilateral shrunken kidneys with altered cortico-medullary distinction. a) What is your provisional diagnosis? b) Describe the morphological changes in the kidneys.