## **Core Concept**
The question describes a clinical presentation suggestive of a gastrointestinal disorder characterized by abdominal pain, fat malabsorption, and frothy stools. This combination of symptoms points towards an intestinal infection or a condition affecting nutrient absorption.

## **Why the Correct Answer is Right**
The correct answer, **Giardiasis (c)**, is caused by the protozoan parasite *Giardia lamblia*. Giardiasis is known for causing malabsorption, particularly of fats, leading to steatorrhea (fatty stools), which can appear frothy. The parasite adheres to the intestinal mucosa, impairing nutrient absorption. Abdominal pain and bloating are also common symptoms.

## **Why Each Wrong Option is Incorrect**
- **Option A: Amoebiasis** is caused by *Entamoeba histolytica* and primarily presents with bloody diarrhea, abdominal pain, and sometimes liver abscesses. While it causes abdominal pain, it is less commonly associated with fat malabsorption and frothy stools.
- **Option B: Bacillary dysentery** is caused by *Shigella* species and typically presents with acute diarrhea, often with blood and mucus, fever, and abdominal cramps. It does not characteristically cause fat malabsorption or frothy stools.
- **Option D: Pancreatic enzyme deficiency** can indeed cause fat malabsorption and steatorrhea due to the lack of digestive enzymes. However, the presence of frothy stools is more characteristic of giardiasis, and pancreatic enzyme deficiency might not primarily present with abdominal pain as a defining feature.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that giardiasis often results in **traveler's diarrhea** and is a common cause of intestinal infections in travelers returning from endemic areas. The presence of frothy, greasy stools is particularly suggestive of giardiasis.

## **Correct Answer: C. Giardiasis**