## **Core Concept**
The question tests understanding of monoamine oxidase inhibitors (MAOIs), specifically targeting the subtype B of monoamine oxidase (MAO-B). MAO-B is an enzyme involved in the breakdown of dopamine and other neurotransmitters. Selective MAO-B inhibitors are used in the treatment of Parkinson's disease.

## **Why the Correct Answer is Right**
Selegiline is a specific and irreversible inhibitor of monoamine oxidase B (MAO-B). By inhibiting MAO-B, selegiline decreases the breakdown of dopamine in the brain, which helps to alleviate symptoms of Parkinson's disease. At therapeutic doses, selegiline is selective for MAO-B over MAO-A, which makes it useful for treating Parkinson's disease with fewer side effects related to dietary tyramine intake.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because the drug listed does not correspond with known MAO-B inhibitors.
- **Option B:** This option is incorrect as it does not represent a known selective MAO-B inhibitor.
- **Option D:** This option is incorrect because it does not accurately represent a drug used as a selective MAO-B inhibitor.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that selegiline is often used as an adjunct in the treatment of Parkinson's disease and is also known for its neuroprotective effects. It's crucial to remember that while selective MAO-B inhibitors like selegiline have a better side effect profile compared to non-selective MAOIs, they can still have interactions, particularly with certain medications and foods.

## **Correct Answer:** C. Selegiline.