**Core Concept**
The yellowing of the skin in hypothyroidism is a manifestation of carotenemia, which occurs due to the accumulation of carotenoid pigments in the skin. This condition is often seen in patients with prolonged fasting, malabsorption, or a diet rich in carotenoids.

**Why the Correct Answer is Right**
Carotenemia occurs due to the accumulation of beta-carotene, a precursor to vitamin A, in the skin. In hypothyroidism, the decreased metabolic rate leads to a reduction in the clearance of carotenoids from the body. As a result, the skin takes on a yellowish hue due to the accumulation of these pigments. The liver plays a crucial role in the metabolism of carotenoids, and in hypothyroidism, the reduced liver function leads to impaired clearance of carotenoids.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not directly relate to the cause of yellowing of the skin in hypothyroidism. While jaundice can cause yellowing of the skin, it is typically associated with liver dysfunction or hemolysis, not hypothyroidism.
**Option B:** This option is incorrect because it refers to a condition characterized by a decrease in melanin production, leading to a loss of skin pigmentation, not yellowing.
**Option C:** This option is incorrect because it refers to a condition characterized by an increase in melanin production, leading to skin darkening, not yellowing.

**Clinical Pearl / High-Yield Fact**
In patients with hypothyroidism, carotenemia can be a useful clinical clue, as it is often accompanied by other signs of hypothyroidism such as dry skin, hair loss, and fatigue.

**Correct Answer: D. Carotenemia due to impaired clearance of carotenoids.**