**Core Concept**
Gout is a form of inflammatory arthritis characterized by deposition of monosodium urate crystals in the joints. Management of chronic gout involves reducing serum urate levels to prevent crystal formation. Uricosuric agents increase uric acid excretion in the urine, while other drugs like allopurinol reduce uric acid production.

**Why the Correct Answer is Right**
The drug that is useful in chronic gout but is NOT a uricosuric agent is allopurinol. Allopurinol works by inhibiting the enzyme xanthine oxidase, which is involved in the production of uric acid. By reducing the production of uric acid, allopurinol helps to decrease serum urate levels and prevent gout attacks. This mechanism is distinct from uricosuric agents, which increase the excretion of uric acid in the urine.

**Why Each Wrong Option is Incorrect**
* **Option A:** Probenecid is a uricosuric agent that increases the excretion of uric acid in the urine. It is not the correct answer because it is a uricosuric agent.
* **Option B:** Sulfinpyrazone is another uricosuric agent that increases the excretion of uric acid in the urine. It is not the correct answer because it is a uricosuric agent.
* **Option D:** Benzbromarone is also a uricosuric agent that increases the excretion of uric acid in the urine. It is not the correct answer because it is a uricosuric agent.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that allopurinol is not a uricosuric agent and should not be used in patients with kidney impairment, as it can cause renal toxicity. Additionally, allopurinol should be started at a low dose and gradually increased to prevent acute gout attacks.

**Correct Answer:** C. Allopurinol.