**Core Concept**
Hourglass stomach, also known as gastric constriction or gastric band, is a rare condition characterized by a narrowing of the stomach, creating a constricted or "hourglass" shape. This condition is often caused by a combination of factors, including gastric motility disorders, scarring, or adhesions that constrict the stomach.

**Why the Correct Answer is Right**
The hourglass stomach is typically seen in patients with a history of gastric surgery, such as gastric bypass or gastric banding. The constriction occurs due to scarring and adhesions that form between the stomach and adjacent tissues, leading to a narrowing of the stomach lumen. This condition can cause symptoms such as abdominal pain, nausea, vomiting, and difficulty swallowing.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specifically relate to the condition of hourglass stomach. While gastric cancer can cause narrowing of the stomach, it is not the primary cause of hourglass stomach.
**Option B:** This option is incorrect because it is a symptom of hourglass stomach, not a cause. Patients with hourglass stomach may experience difficulty swallowing, but this is a result of the constriction, not a cause of the condition.

**Clinical Pearl / High-Yield Fact**
It's essential to note that hourglass stomach is a rare condition, but it can be a complication of gastric surgery. Therefore, it's crucial for surgeons and gastroenterologists to be aware of this potential complication and take steps to prevent it during and after surgery.

**Correct Answer: C.**