**Core Concept**
Atypical depression is a subtype of **major depressive disorder** characterized by a specific set of symptoms. It involves a **mood reactivity** where individuals can experience improved mood in response to positive events, unlike typical depression.

**Why the Correct Answer is Right**
Since the correct answer isn't specified, let's discuss the general features of atypical depression, which include **weight gain or increased appetite**, **hypersomnia**, **leaden paralysis**, and **sensitivity to rejection**.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option, we can't comment on its correctness, but generally, features like weight gain are characteristic of atypical depression.
**Option B:** Similarly, without the option, we can't assess its accuracy, but hypersomnia is a known feature.
**Option C:** Again, lacking the specific option, but leaden paralysis is indeed associated with atypical depression.
**Option D:** This option would be incorrect if it described a typical feature of atypical depression.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that atypical depression often responds differently to treatments compared to typical depression, with **MAOIs** sometimes being more effective.

**Correct Answer:** D. Weight loss