**Core Concept**
Tay-Sachs disease is a rare, inherited disorder caused by a deficiency of an enzyme responsible for breaking down fatty substances in the brain, particularly in the neurons of the central nervous system.

**Why the Correct Answer is Right**
The enzyme deficient in Tay-Sachs disease is **hexosaminidase A**. This enzyme is crucial for the breakdown of GM2 gangliosides, a type of fatty substance found in the brain. Without sufficient hexosaminidase A, GM2 gangliosides accumulate and cause cellular damage, leading to the characteristic symptoms of Tay-Sachs disease, such as progressive weakness, loss of motor skills, and mental deterioration.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the enzyme involved in Tay-Sachs disease.
**Option B:** This option is incorrect because it refers to a different lysosomal storage disorder, Pompe disease, which is caused by a deficiency of acid alpha-glucosidase.
**Option C:** This option is incorrect because it refers to a different enzyme involved in a different metabolic pathway.

**Clinical Pearl / High-Yield Fact**
Tay-Sachs disease is an autosomal recessive disorder, meaning that a person must inherit two copies of the mutated gene (one from each parent) to develop the disease.

**Correct Answer:** B. Hexosaminidase A.