**Core Concept**
Hourglass deformity refers to the constriction or narrowing of a hollow viscus, typically resulting from fibrosis, scarring, or contraction of the intestinal wall. This phenomenon is often observed in conditions that involve chronic inflammation or ulceration of the gastrointestinal tract.

**Why the Correct Answer is Right**
The hourglass deformity in peptic ulcer disease occurs due to chronic inflammation and scarring of the gastric or duodenal mucosa, leading to fibrosis and contraction of the affected segment. This results in a characteristic narrowing or constriction of the intestine, resembling an hourglass. The chronic inflammation and scarring are typically caused by the continuous exposure of the gastric or duodenal mucosa to acid and pepsin, leading to ulceration and subsequent fibrosis.

**Why Each Wrong Option is Incorrect**
**Option A:** Carcinoma stomach can cause a variety of gastrointestinal symptoms, but it is not typically associated with the characteristic hourglass deformity seen in peptic ulcer disease. While carcinoma can cause intestinal obstruction, it usually results in a more diffuse or irregular narrowing.
**Option C:** Duodenal atresia is a congenital anomaly characterized by a complete obstruction of the duodenum, typically presenting in neonates. It does not typically result in the hourglass deformity seen in peptic ulcer disease.
**Option D:** CHPS (Congenital Hypertrophic Pyloric Stenosis) is a condition characterized by hypertrophy of the pyloric muscle, leading to gastric outlet obstruction. While it can cause a narrowing of the pyloric channel, it does not typically result in the hourglass deformity seen in peptic ulcer disease.

**Clinical Pearl / High-Yield Fact**
The hourglass deformity is a classic radiological finding in peptic ulcer disease, but it can also be seen in other conditions that involve chronic inflammation and scarring of the gastrointestinal tract, such as Crohn's disease or chronic intestinal ischemia. A high index of suspicion is necessary to diagnose this condition, as it can have significant implications for patient management and treatment.

✓ Correct Answer: B. Peptic ulcer