## **Core Concept**
The question tests knowledge on the impact of severe infectious enteritis on intestinal enzyme activity, particularly in children. Infectious enteritis can lead to damage of the intestinal mucosa, affecting the production of various enzymes crucial for nutrient digestion and absorption.

## **Why the Correct Answer is Right**
Lactase is an enzyme responsible for breaking down lactose, a sugar found in milk and other dairy products, into glucose and galactose for absorption. Severe infectious enteritis can cause damage to the intestinal mucosa, leading to a decrease or temporary absence of lactase production. This condition is known as secondary or acquired lactose intolerance. The deficiency of lactase leads to an inability to digest lactose properly, resulting in symptoms like bloating, gas, and diarrhea after consuming lactose-containing products.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because while various enzymes could be affected, the question specifically points towards a commonly recognized issue following infectious enteritis.
- **Option B:** This option is incorrect as there's no commonly recognized enzyme labeled simply as "B" in the context of digestive enzymes related to the question.
- **Option D:** This option is incorrect because, although several enzymes could be impacted, the specific and well-documented consequence of infectious enteritis relates to lactase deficiency.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that children (and adults) can develop secondary lactose intolerance following an episode of severe infectious enteritis. This condition is usually temporary, and lactase activity can recover once the intestinal mucosa heals. Diagnosis can be made with a hydrogen breath test, and management involves a lactose-restricted diet or lactase enzyme supplementation.

## **Correct Answer:** .