**Core Concept**
Tumor lysis syndrome (TLS) is a life-threatening condition that occurs when a large number of cancer cells die rapidly, releasing their contents into the bloodstream. This leads to a buildup of toxic substances, including potassium, phosphate, and uric acid, which can cause severe complications.

**Why the Correct Answer is Right**
The key features of TLS include hyperkalemia (elevated potassium levels), hyperphosphatemia (elevated phosphate levels), hypocalcemia (low calcium levels), and hyperuricemia (elevated uric acid levels). The rapid release of intracellular contents from dying cancer cells leads to an increase in potassium and phosphate, while the breakdown of nucleic acids results in the production of uric acid. The increased phosphate levels then bind to calcium, forming insoluble calcium phosphate complexes, which decreases the calcium levels in the blood.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because hyperkalemia is a characteristic feature of TLS.
* **Option B:** This option is incorrect because hyperphosphatemia is also a hallmark of TLS.
* **Option D:** This option is incorrect because hyperuricemia is a key feature of TLS, resulting from the breakdown of nucleic acids from dying cancer cells.

**Clinical Pearl / High-Yield Fact**
A mnemonic to remember the key features of TLS is "KPKU" - potassium, phosphate, potassium, and uric acid. This helps clinicians identify the laboratory abnormalities associated with this condition.

**Correct Answer: C.**