**Core Concept**
Elevated intra-abdominal pressure, decreased lower esophageal sphincter (LES) pressure, and impaired esophageal clearance are key factors contributing to gastroesophageal reflux disease (GERD). To prevent GERD, one must address these underlying mechanisms.

**Why the Correct Answer is Right**
The correct answer is a type of medication that increases the lower esophageal sphincter tone, thus preventing reflux. This action is primarily mediated through the cholinergic pathway, where acetylcholine binds to muscarinic receptors on the smooth muscle cells of the LES, causing contraction and increased pressure. This contraction helps to prevent gastric reflux into the esophagus.

**Why Each Wrong Option is Incorrect**
**Option A:**
This option is incorrect because antacids and H2 blockers only neutralize gastric acid and reduce acid production, respectively. They do not address the underlying mechanism of impaired LES tone or elevated intra-abdominal pressure.

**Option B:**
This option is incorrect because prokinetic agents like metoclopramide increase gastric emptying and motility. While they may help alleviate symptoms of GERD, they do not address the underlying issue of impaired LES tone.

**Option C:**
This option is incorrect because antireflux surgery, such as fundoplication, is a surgical intervention that addresses the anatomical issues contributing to GERD. However, it is not a pharmacological option.

**Clinical Pearl / High-Yield Fact**
In the management of GERD, it is essential to address the underlying mechanisms contributing to the disease, rather than just managing symptoms. Increasing LES tone and reducing intra-abdominal pressure can be achieved through various pharmacological and non-pharmacological means.

**Correct Answer:** D.