**Core Concept**
The posterior gastric artery is a branch of the splenic artery, which is a major branch of the celiac trunk. This artery supplies the posterior aspect of the stomach, playing a crucial role in its blood supply.

**Why the Correct Answer is Right**
The posterior gastric artery arises from the splenic artery, which is a direct branch of the celiac trunk. This artery then travels along the greater curvature of the stomach, supplying the posterior gastric wall. The splenic artery also gives off branches to the pancreas and spleen. The posterior gastric artery is an important branch for maintaining the blood supply to the stomach, especially during surgical procedures.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the left gastroepiploic artery, a branch of the splenic artery, primarily supplies the greater curvature of the stomach, not the posterior aspect.
**Option B:** This option is incorrect because the right gastroepiploic artery, a branch of the gastroduodenal artery, primarily supplies the lesser curvature of the stomach, not the posterior aspect.
**Option C:** This option is incorrect because the short gastric arteries, branches of the splenic artery, primarily supply the fundus of the stomach, not the posterior aspect.

**Clinical Pearl / High-Yield Fact**
Remember that the posterior gastric artery is an important branch of the splenic artery, and its preservation is crucial during gastric surgery to maintain the blood supply to the stomach.

**Correct Answer: C. The splenic artery.**