**Core Concept**
Zollinger-Ellison syndrome is a rare disorder characterized by excessive gastric acid secretion due to high levels of gastrin, a hormone produced by a gastrinoma (a type of neuroendocrine tumor). The condition leads to severe peptic ulcers and diarrhea.

**Why the Correct Answer is Right**
The drug of choice for Zollinger-Ellison syndrome is a proton pump inhibitor (PPI) that can effectively reduce gastric acid secretion. Proton pump inhibitors work by irreversibly inhibiting the H+/K+ ATPase enzyme system at the secretory surface of gastric parietal cells, thereby reducing gastric acid production. This mechanism allows PPIs to provide potent and long-lasting acid suppression, making them ideal for managing the symptoms of Zollinger-Ellison syndrome.

**Why Each Wrong Option is Incorrect**
**Option A:** Histamine-2 (H2) receptor antagonists, such as ranitidine, are not the first-line treatment for Zollinger-Ellison syndrome because they do not offer sufficient acid suppression compared to PPIs.
**Option B:** Antacids and sucralfate may provide temporary relief from symptoms but do not address the underlying pathophysiology of the condition and are not effective in managing severe peptic ulcers.
**Option C:** Anticholinergics, such as atropine, can reduce gastric acid secretion by inhibiting the action of the vagus nerve. However, they are not as effective as PPIs and can have significant side effects, making them a less desirable option.

**Clinical Pearl / High-Yield Fact**
In patients with Zollinger-Ellison syndrome, it is essential to consider the possibility of a gastrinoma and refer them to an endocrinologist or a gastroenterologist for further evaluation and management.

**Correct Answer: C. Proton pump inhibitors.**