Okay, let's tackle this question. The patient has diarrhea and abdominal distension, and the biopsy shows villous atrophy and crypt hyperplasia. Hmm, those are the key signs here. Villous atrophy is a classic finding in celiac disease, right? Because in celiac, the immune response to gluten damages the villi in the small intestine, leading to malabsorption. Crypt hyperplasia is a compensatory response where the crypts try to regenerate the villi.

So the options might be celiac disease, but what about other possibilities? Let's think. Lactose intolerance could cause diarrhea, but it doesn't lead to villous atrophy. Crohn's disease usually affects the terminal ileum and has a transmural inflammation, not just villous changes. Whipple's disease involves PAS-positive macrophages, not atrophy. Tropical sprue is another possibility but it's more common in certain geographic areas and might have similar features but less specific.

The correct answer is celiac disease. The key histological findings here are the atrophy of the villi and the hyperplasia of the crypts. Celiac is an autoimmune disorder triggered by gluten. The biopsy findings, along with symptoms like diarrhea, abdominal distension, and possible malabsorption (like weight loss, steatorrhea), all point to this diagnosis. The other options don't fit the histology as well. For example, Crohn's would have granulomas and transmural involvement. Lactose intolerance is a functional issue without structural changes. So the answer must be celiac disease.

**Core Concept**
This question tests recognition of histopathological features in small intestinal biopsy for diagnosing malabsorption disorders. Villous atrophy and crypt hyperplasia are hallmark findings in **celiac disease**, an autoimmune gluten-sensitive enteropathy.

**Why the Correct Answer is Right**
Celiac disease triggers an immune-mediated response to gluten ingestion, leading to damage in the duodenum and proximal jejunum. The immune reaction involves **tissue transglutaminase (tTG) antibodies** and **CD8+ T cells**, causing destruction of intestinal villi (flattened architecture) and compensatory crypt hyperplasia. Symptoms like diarrhea, abdominal distension, and malabsorption align with this diagnosis. Confirmatory tests include **serology (anti-tTG IgA, EMA)** and biopsy showing **villous atrophy (Marsh type 3)**.

**Why Each Wrong Option is Incorrect**
**Option A:** *Lactose intolerance* causes osmotic diarrhea but spares villous architecture.
**Option B:** *Crohn’s disease* presents with transmural inflammation, granulomas, and skip lesions—not villous atrophy.
**Option C:** *Whipple’s disease* involves PAS-positive macrophages and foamy histiocytes, not villous atrophy.

**Clinical Pearl / High-Yield Fact**
**"Celiac triad"** includes diarrhea, weight loss, and iron-deficiency anemia. Remember **“3 Ds”**: Dermatitis herpetiformis, Diarrhea, and Dermatological symptoms. Always consider celiac in patients with unexplained malabsorption and villous atrophy on biopsy.

**Correct Answer: C. Celiac disease**

✓ Correct Answer: A. Celiac sprue