**Question:** Congenital pyloric stenosis presents with:

A. Abdominal distension
B. Vomiting
C. Poor feeding
D. Diarrhoea

**Core Concept:**
Congenital pyloric stenosis is a condition that occurs when the pylorus, the muscular ring at the junction of the stomach and duodenum, becomes narrowed or obstructed. This results in impaired gastric emptying and can cause symptoms related to gastrointestinal dysfunction.

**Why the Correct Answer is Right:**
Congenital pyloric stenosis is a condition that presents with symptoms related to impaired gastric emptying. In this case, the correct answer (C) is related to poor feeding due to inadequate absorption of nutrients from the food ingested. Poor feeding is a direct consequence of the narrowed pylorus, which leads to incomplete gastric emptying and malabsorption.

**Why Each Wrong Option is Incorrect:**
A. Abdominal distension (option A) can be present in other conditions like gastrointestinal obstruction, but not specifically due to pyloric stenosis.
B. Vomiting (option B) can be present in various gastrointestinal disorders, but poor feeding is a more specific symptom of pyloric stenosis.
D. Diarrhoea (option D) may present in other conditions like lactose intolerance or gastroenteritis but is not a typical feature of pyloric stenosis.

**Clinical Pearl:**
In cases of suspected congenital pyloric stenosis, focusing on the specific symptoms like poor feeding and vomiting can help in narrowing down the differential diagnoses. Clinical correlation with the patient's history and examination findings is crucial in reaching a correct diagnosis. A thorough evaluation, including an abdominal ultrasound, is often necessary to confirm pyloric stenosis.

**Correct Answer:** C. Poor feeding