Investigation in a patient of oliguria revealed Urine osmolity 620 mosm/kg Urine sodium :12mmol/L Urine /plasma urea ratio :13 :1 The most likely diagnosis is -: (A) Prerenal acute renal failure, (B) Acute tubular recrosis, (C) Acute cortical necrosis, (D) Urinary tract obstruction
Answer is A. None