**Core Concept**
Uric acid is a waste product formed in humans through the breakdown of purine nucleotides, which are components of DNA and RNA. This process occurs primarily in the liver and involves the enzyme xanthine oxidase.

**Why the Correct Answer is Right**
The breakdown of purine nucleotides starts with the conversion of hypoxanthine to xanthine by the enzyme xanthine oxidase. Xanthine oxidase then converts xanthine to uric acid. This enzyme is found in high concentrations in the liver, where it plays a crucial role in the metabolism of purines. Elevated levels of xanthine oxidase can lead to increased production of uric acid, contributing to conditions such as gout.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the correct location or enzyme involved in the formation of uric acid.
**Option B:** This option is incorrect because it refers to a different metabolic pathway, involving the breakdown of glucose to carbon dioxide and water.
**Option C:** This option is incorrect because it is a byproduct of uric acid metabolism, not the primary site of its formation.

**Clinical Pearl / High-Yield Fact**
One important clinical consideration is that elevated levels of xanthine oxidase can be exacerbated by certain medications, such as allopurinol, which inhibit the enzyme and increase the risk of gout attacks in susceptible individuals.

**Correct Answer: C. Liver**