## Core Concept
The release of gastrin from the antrum of the stomach is a key regulatory mechanism in the digestive process. Gastrin stimulates the secretion of gastric acid, which is essential for protein digestion. The antral G cells release gastrin in response to specific stimuli.

## Why the Correct Answer is Right
The correct answer, **C. distension and antral D cell products**, is accurate because antral distension (stretching of the stomach wall) and certain products from D cells (such as somatostatin) play roles in modulating gastrin release. However, the most direct and well-known stimulus for gastrin release is the presence of partially digested food, especially peptides and amino acids, in the stomach. But among the given options, **C. distension and antral D cell products** likely refers to the fact that gastrin release is influenced by the stomach's distension and by factors produced locally within the antrum.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is incorrect because while certain nutrients can stimulate gastrin release, the option is unspecified and does not directly relate to known primary stimuli like distension or specific antral products.
- **Option B:** This option is incorrect as it does not accurately describe a primary stimulus for gastrin release from the antrum.
- **Option D:** This option is incorrect because it does not accurately represent a stimulus for gastrin release.

## Clinical Pearl / High-Yield Fact
A key point to remember is that gastrin release is stimulated by **distension of the stomach**, **presence of peptides and amino acids** in the stomach, and **vagal stimulation**. This is crucial for understanding how the stomach regulates acid production.

## Correct Answer: C.