**Core Concept**
Monoamine oxidase inhibitors (MAOIs) are a class of medications used to treat depression and other psychiatric disorders. Non-selective MAOIs inhibit both MAO-A and MAO-B enzymes, which are involved in the breakdown of various neurotransmitters, including serotonin, norepinephrine, and dopamine.

**Why the Correct Answer is Right**
The correct answer is a non-selective MAOI because it inhibits both MAO-A and MAO-B enzymes. MAO-A primarily breaks down serotonin and norepinephrine, while MAO-B primarily breaks down dopamine. Inhibiting both enzymes leads to increased levels of these neurotransmitters, which can help alleviate symptoms of depression. The non-selective MAOI acts by irreversibly binding to the MAO enzyme, preventing the breakdown of these neurotransmitters.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a selective MAOI that only inhibits MAO-A or MAO-B, but not both. Selective MAOIs have a lower risk of side effects, but may not be as effective as non-selective MAOIs for certain patients.
**Option B:** This option is incorrect because it is a type of medication that is not an MAOI. It may have a different mechanism of action or target a different neurotransmitter system.
**Option C:** This option is incorrect because it is a type of medication that is not commonly classified as an MAOI. It may have a different mechanism of action or target a different neurotransmitter system.

**Clinical Pearl / High-Yield Fact**
Non-selective MAOIs can cause a dangerous interaction with certain foods, such as tyramine-rich foods, which can lead to a sudden increase in blood pressure. Patients taking non-selective MAOIs should avoid these foods and be monitored closely for signs of hypertensive crises.

**Correct Answer: C. phenelzine**