## **Core Concept**
The question tests knowledge of enzyme deficiencies related to specific diseases, focusing on beta-glucosidase. Beta-glucosidase is an enzyme involved in the breakdown of certain lipids. Its deficiency leads to a particular lysosomal storage disorder.

## **Why the Correct Answer is Right**
The correct answer, **C. Gaucher's disease**, is linked to a deficiency of the enzyme beta-glucosidase (also known as glucocerebrosidase). This enzyme is crucial for breaking down glucocerebroside, a type of lipid, into glucose and ceramide. Without sufficient beta-glucosidase activity, glucocerebroside accumulates within cells, particularly in macrophages, leading to the characteristic features of Gaucher's disease.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Tay-Sachs disease is caused by a deficiency of the enzyme hexosaminidase A, not beta-glucosidase. This deficiency leads to the accumulation of GM2 ganglioside within neurons.
- **Option B:** Pompe disease results from a deficiency of the enzyme acid alpha-glucosidase (acid maltase), which is involved in glycogen breakdown. This is distinct from beta-glucosidase.
- **Option D:** Niemann-Pick disease is primarily associated with a deficiency in acid sphingomyelinase, an enzyme involved in the breakdown of sphingomyelin.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that Gaucher's disease is one of the lysosomal storage diseases that can be treated with enzyme replacement therapy (ERT), which involves administering the deficient enzyme to patients. This treatment can significantly improve the clinical outcomes for individuals with Gaucher's disease.

## **Correct Answer:** C. Gaucher's disease