**Core Concept**
The question is testing the student's knowledge of the latest advancements in antidepressant pharmacology. **Selective Serotonin Reuptake Inhibitors (SSRIs)** and **Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)** are two classes of antidepressants that have been widely used for treating depression. However, the question is asking about a newer class of antidepressants.

**Why the Correct Answer is Right**
The correct answer is a newer class of antidepressants that targets the **N-methyl-D-aspartate (NMDA) receptor**. This class of antidepressants is known as **Ketamine-Related Antidepressants** or **Glutamate Modulators**. They work by increasing the activity of glutamate in the brain, which helps to improve mood and reduce symptoms of depression. **AVP (Vasopressin) Receptor Antagonists** are also a newer class of antidepressants that are being studied for their potential in treating treatment-resistant depression.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a newer class of antidepressants. SSRIs and SNRIs have been widely used for treating depression, but they are not the newest class of antidepressants.

**Option B:** This option is incorrect because it is not a specific class of antidepressants. The term "antidepressant" is too broad and does not provide any information about the mechanism of action or the specific class of medication.

**Option C:** This option is incorrect because it is not a well-known class of antidepressants. While some medications may have a similar mechanism of action, this option is not specific or accurate.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that the newest class of antidepressants targets the NMDA receptor and works by increasing the activity of glutamate in the brain. This is a key concept in understanding the mechanism of action of these medications and how they can be used to treat treatment-resistant depression.

**Correct Answer:** D. **SCH 900222 (Esketamine)**