**Core Concept**
The question tests the understanding of **dermatological disorders**, specifically those characterized by hyperpigmented macules and a particular response to physical stimuli. The key concept here involves **mast cell degranulation** and the resulting clinical manifestations.

**Why the Correct Answer is Right**
The correct answer is related to a condition where **mast cells** play a crucial role. The description points towards **mastocytosis**, a condition where there is an accumulation of mast cells in the skin. The **Darier's sign** is a characteristic feature, where gentle rubbing of the lesion leads to **urticarial wheal** formation due to mast cell degranulation and histamine release.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not typically present with hyperpigmented macules and a positive Darier's sign.
**Option B:** Not relevant to the specific clinical findings described.
**Option C:** Does not match the clinical scenario provided, lacking the key feature of mast cell degranulation upon rubbing.

**Clinical Pearl / High-Yield Fact**
A key point to remember is the **Darier's sign**, which is pathognomonic for **mastocytosis** in the skin. This sign is crucial for differentiating mastocytosis from other dermatological conditions.

**Correct Answer:** D. Mastocytosis.