A nurse is teaching a client who has acute kidney injury about the oliguric phase. Which of the following information should the nurse include in the teaching?

A. GFR recovery does not occur during the oliguric phase; it remains low. B. BUN and creatinine levels increase during the oliguric phase due to reduced filtration. C. Urine output less than 400 mL in 24 hours defines the oliguric phase and is a hallmark feature. D. Renal function reestablishment occurs later, during the recovery phase, not the oliguric phase.