**Core Concept**
Zollinger Ellison syndrome is a rare disorder characterized by excessive gastric acid secretion due to high levels of gastrin, often caused by a gastrinoma, a type of neuroendocrine tumor. The condition leads to severe peptic ulcer disease and diarrhea.

**Why the Correct Answer is Right**
The drug of choice in Zollinger Ellison syndrome is a proton pump inhibitor (PPI), specifically **omeprazole**. PPIs irreversibly inhibit the H+/K+ ATPase enzyme system at the secretory surface of gastric parietal cells, resulting in a significant reduction in gastric acid secretion. This makes PPIs highly effective in managing the symptoms of Zollinger Ellison syndrome.

**Why Each Wrong Option is Incorrect**
* **Option A:** H2 receptor antagonists, such as ranitidine, are less potent than PPIs in reducing gastric acid secretion and are not the preferred choice for managing Zollinger Ellison syndrome.
* **Option B:** Antacids and histamine-2 (H2) blockers are often used as initial treatment for mild peptic ulcer disease but are not sufficient for the high levels of acid production seen in Zollinger Ellison syndrome.
* **Option C:** Somatostatin analogues, such as octreotide, may be used to control gastrin levels in Zollinger Ellison syndrome, but they are not the primary treatment and often used in combination with PPIs.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that PPIs are the preferred treatment for Zollinger Ellison syndrome due to their potent inhibition of gastric acid secretion, making them more effective than H2 receptor antagonists or somatostatin analogues in managing the condition.

**Correct Answer:** C. Octreotide