**Core Concept**
The question is testing knowledge of a specific skin finding associated with a metabolic disorder. The correct answer requires identification of a characteristic skin manifestation linked to an underlying metabolic condition.

**Why the Correct Answer is Right**
The skin finding is characteristic of **Hypothyroidism**. In hypothyroidism, the decreased metabolic rate leads to changes in the skin, including dryness, thickening, and a characteristic **Waxy Pallor**. This skin finding is a result of the decreased metabolism, which affects the skin's ability to shed dead cells, leading to a buildup of skin cells and a characteristic waxy appearance.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because **Diabetes Mellitus** is associated with skin findings such as acanthosis nigricans, pruritus, and skin infections, but not waxy pallor.
**Option B:** This option is incorrect because **Hyperthyroidism** is associated with skin findings such as thinning, warmth, and flushing, but not waxy pallor.
**Option C:** This option is incorrect because **Cushing's Syndrome** is associated with skin findings such as striae, acne, and hirsutism, but not waxy pallor.

**Clinical Pearl / High-Yield Fact**
Remember the "4Ds" of hypothyroidism: Dry skin, Decreased hair growth, Decreased libido, and Decreased mental acuity.

**Correct Answer: C. Hypothyroidism.**