**Core Concept**
In the stomach, Hormones play a crucial role in regulating digestion and appetite. Hydrochloric acid (HCI) secretion is a vital process for gastric digestion, and it is facilitated by specific cells in the stomach lining.

**Why the Correct Answer is Right**
HCI secretion is primarily mediated by parietal cells, also known as oxyntic cells, which are found in the gastric glands of the stomach. These cells use a proton pump mechanism to secrete HCI, which is necessary for the activation of digestive enzymes and the breakdown of food. The correct answer is related to the specific cell type responsible for HCI secretion in the stomach.

**Why Each Wrong Option is Incorrect**
**Option A:** Mucous neck cells are responsible for producing mucin, which forms a protective layer over the gastric epithelium. They are not involved in HCI secretion.
**Option B:** Chief cells, also known as peptic cells, produce pepsinogen, the inactive precursor to pepsin, a digestive enzyme. They do not secrete HCI.
**Option C:** Enterochromaffin-like (ECL) cells release histamine, which stimulates HCI secretion by parietal cells. However, ECL cells are not the primary cells responsible for HCI secretion.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that parietal cells are the primary source of HCI secretion in the stomach, and their dysfunction can lead to conditions like achlorhydria or decreased gastric acid production.

**Correct Answer:** C. Parietal cells