**Core Concept**
Tumor lysis syndrome (TLS) and acute kidney injury (AKI) can occur in patients with acute myeloid leukemia (AML) undergoing chemotherapy, leading to hyperuricemia, hyperphosphatemia, and secondary complications such as uric acid nephropathy.

**Why the Correct Answer is Right**
The patient's presentation of oliguric renal failure, acidic urine, and numerous crystals is suggestive of uric acid nephropathy, a complication of tumor lysis syndrome. Uric acid crystals form in the renal tubules, causing direct damage to the renal parenchyma and leading to AKI. The acidic urine pH exacerbates the precipitation of uric acid crystals, contributing to renal injury.

**Why Each Wrong Option is Incorrect**
* **Option A:** Acute interstitial nephritis would not typically present with acidic urine and numerous crystals. It is more commonly associated with fever, rash, and eosinophilia.
* **Option B:** Acute glomerulonephritis would not typically present with acidic urine and numerous crystals. It is more commonly associated with hematuria, proteinuria, and hypertension.
* **Option C:** Acute tubular necrosis would not typically present with acidic urine and numerous crystals. It is more commonly associated with oliguric renal failure and electrolyte imbalances.

**Clinical Pearl / High-Yield Fact**
Tumor lysis syndrome is a medical emergency that requires prompt recognition and treatment to prevent complications such as uric acid nephropathy.

**Correct Answer: C.**