**Core Concept**
COX-2 inhibitors are a class of nonsteroidal anti-inflammatory drugs (NSAIDs) that selectively target cyclooxygenase-2 (COX-2), an enzyme involved in the synthesis of prostaglandins, which mediate inflammation and pain. Preferential COX-2 inhibitors have a higher affinity for COX-2 than COX-1, reducing gastrointestinal side effects associated with traditional NSAIDs.

**Why the Correct Answer is Right**
Celecoxib is a preferential COX-2 inhibitor that works by selectively inhibiting COX-2 enzyme activity in the peripheral tissues, leading to a reduction in prostaglandin synthesis and subsequent inflammation. This mechanism allows for the anti-inflammatory and analgesic effects of celecoxib while minimizing the risk of gastrointestinal ulceration and bleeding associated with COX-1 inhibition. Celecoxib's preferential COX-2 inhibition is attributed to its unique chemical structure, which favors binding to the COX-2 active site.

**Why Each Wrong Option is Incorrect**
**Option A:** (Name of another NSAID) is a non-selective NSAID that inhibits both COX-1 and COX-2 enzymes, increasing the risk of gastrointestinal side effects.
**Option B:** (Name of another COX-2 inhibitor) is a non-preferential COX-2 inhibitor, meaning it has a similar affinity for COX-1 and COX-2 enzymes, offering little advantage over traditional NSAIDs in terms of gastrointestinal safety.
**Option D:** (Name of another medication) is not a COX-2 inhibitor at all, but rather an opioid analgesic with a different mechanism of action.

**Clinical Pearl / High-Yield Fact**
When choosing a COX-2 inhibitor, it is essential to consider the patient's risk factors for gastrointestinal bleeding, as well as their renal function and cardiovascular health. Celecoxib's preferential COX-2 inhibition makes it a suitable option for patients with a history of gastrointestinal ulcers or bleeding.

**Correct Answer: C. Celecoxib**