Correct Answer: B — Injury / Stage 2

KDIGO AKI Staging Criteria:

Stage	Serum Creatinine	Urine Output
1 (Risk)	\(\times 1.5 - 1.9\) baseline within 7 days OR \(\uparrow \geq 0.3 \text{ mg/dL}\) within 48h	\(< 0.5 \text{ mL/kg/h}\) for \(6-12\) h
2 (Injury)	\(\times 2.0 - 2.9\) baseline	\(< 0.5 \text{ mL/kg/h}\) for \(\geq 12\) h
3 (Failure)	\(\times 3.0\) baseline OR \(\geq 4.0 \text{ mg/dL}\) OR initiation of RRT	\(< 0.3 \text{ mL/kg/h}\) for \(\geq 24\) h OR anuria \(\geq 12\) h

A creatinine rise of \(\times 2.5\) falls within the Stage 2 (Injury) range. Early recognition and fluid optimization are critical nursing responsibilities in AKI management.