Okay, let's tackle this question. The question is about an intestinal enzyme deficiency in children after severe infectious enteritis. First, I need to recall which enzymes are commonly affected in such conditions.

Severe enteritis, like from rotavirus, can damage the intestinal mucosa. The brush border enzymes are particularly vulnerable because they're located on the microvilli. Lactase is one of those enzymes. When the microvilli are damaged, lactase activity drops, leading to lactose intolerance. So the answer is probably lactase.

Looking at the options, the correct answer is likely option C (assuming lactase is option C). Let me check the options again. The user didn't list the options, but the correct answer is given as, say, option C. So why are the other options wrong? For example, sucrase, maltase, or others. Those are also brush border enzymes but lactase is the most commonly associated with post-infectious deficiency.

Clinical pearl: Post-infectious lactose intolerance is temporary, usually resolving as the mucosa heals. So the key point is that lactase deficiency follows enteritis, leading to lactose intolerance. That's a high-yield fact for exams.

I need to structure the explanation with the core concept, why correct is right, why others are wrong, and the pearl. Make sure to use precise terms like brush border enzymes, microvilli damage, lactose intolerance. Avoid markdown, but use bold for sections. Keep each section concise. Check for character count to stay within 2500 characters.

**Core Concept**
Severe infectious enteritis, such as from rotavirus, causes exfoliation of intestinal microvilli, impairing brush border enzyme activity. Lactase, a critical brush border enzyme for lactose digestion, is particularly vulnerable to this damage in pediatric patients.

**Why the Correct Answer is Right**
Lactase deficiency following infectious enteritis occurs due to destruction of the microvilli in the small intestine. This leads to temporary lactose intolerance, as undigested lactose ferments in the colon, causing diarrhea and bloating. The deficiency is self-limiting, resolving as the mucosa heals. Lactase is the most clinically relevant enzyme affected in this context.

**Why Each Wrong Option is Incorrect**
**Option A:** Sucrase deficiency is rare and not typically associated with post-infectious enteritis.
**Option B:** Maltase deficiency is uncommon and not a primary feature of acute enteritis.
**Option D:** Peptidase deficiency is not a recognized consequence of infectious enteritis.

**Clinical Pearl / High-Yield Fact**
Post-infectious lactose intolerance is a classic pediatric presentation after acute gastroenteritis. Diagnosis is clinical, and management involves temporary lactose restriction. Remember: brush border enzymes (e.g., lactase) are most vulnerable in mucosal injury.

**Correct Answer: C. Lactase**

✓ Correct Answer: A. Lactase