**Core Concept**
Prostaglandins play a crucial role in maintaining the protective mucosal lining of the stomach. NSAIDs inhibit the enzyme cyclooxygenase (COX), which results in decreased prostaglandin production and subsequent gastric mucosal damage.

**Why the Correct Answer is Right**
Misoprostol is a synthetic prostaglandin E1 analogue that protects the gastric mucosa by replacing the prostaglandins that are depleted due to NSAID use. It works by stimulating the release of bicarbonate and mucus, which helps to protect the stomach lining from acid and pepsin. By doing so, misoprostol reduces the risk of NSAID-induced gastric ulcers.

**Why Each Wrong Option is Incorrect**
**Option A:** Ranitidine, an H2 receptor antagonist, can reduce acid production in the stomach but does not address the underlying mucosal damage caused by NSAIDs.
**Option B:** Sucralfate forms a protective barrier over the ulcer site, but it does not directly replace the prostaglandins that are depleted due to NSAID use.
**Option C:** Omeprazole, a proton pump inhibitor, reduces acid production in the stomach but does not provide the same level of mucosal protection as prostaglandins.

**Clinical Pearl / High-Yield Fact**
When treating NSAID-induced gastric ulcers, it's essential to consider the use of a prostaglandin analogue like misoprostol to provide mucosal protection.

**Correct Answer:** A. Misoprostol.