**Core Concept**
Monoamine oxidase B (MAO-B) inhibitors are a class of medications used to treat Parkinson's disease and depression. They work by inhibiting the enzyme monoamine oxidase B, which breaks down dopamine in the brain, thereby increasing its concentration.

**Why the Correct Answer is Right**
The enzyme monoamine oxidase B (MAO-B) is specifically targeted by these medications to prevent the breakdown of dopamine. This leads to an increase in dopamine levels, alleviating symptoms of Parkinson's disease and depression. MAO-B inhibitors do not affect monoamine oxidase A (MAO-A), which is involved in the breakdown of other neurotransmitters.

**Why Each Wrong Option is Incorrect**
**Option A:** Selegiline is a well-known MAO-B inhibitor used in the treatment of Parkinson's disease.
**Option B:** Rasagiline is another MAO-B inhibitor used to treat Parkinson's disease, with a lower risk of dietary restrictions compared to traditional MAO-B inhibitors.
**Option C:** Moclobemide is actually a reversible inhibitor of monoamine oxidase A (RIMA), not a MAO-B inhibitor.

**Clinical Pearl / High-Yield Fact**
When prescribing MAO-B inhibitors, it's essential to note that they have a "cheese reaction," which is a potentially life-threatening interaction with tyramine-rich foods like aged cheese, wine, and chocolate. Patients should be advised to avoid these foods to prevent hypertensive crises.

**Correct Answer:** C. Moclobemide