**Core Concept**
The hormone associated with satiety is a vital component of the complex physiological process regulating food intake and energy balance. The hormone in question plays a crucial role in signaling the brain when the body has consumed sufficient nutrients, thereby preventing excessive caloric intake.

**Why the Correct Answer is Right**
The hormone responsible for satiety is **Leptin**. Leptin is produced by adipose tissue and acts on the hypothalamus to suppress appetite and increase energy expenditure. Leptin binds to its receptor, which triggers a signaling cascade that ultimately leads to the inhibition of orexigenic (appetite-stimulating) neurons and the activation of anorexigenic (appetite-suppressing) neurons. This complex interplay between leptin and the hypothalamus helps maintain energy homeostasis.

**Why Each Wrong Option is Incorrect**
* **Option A:** Ghrelin is often referred to as the "hunger hormone" because it stimulates appetite and increases food intake. Therefore, it is not associated with satiety.
* **Option B:** Insulin is a hormone involved in glucose regulation and does not directly influence satiety. While insulin can affect food intake indirectly by reducing glucose levels, it is not the primary hormone associated with satiety.
* **Option C:** Cholecystokinin (CCK) is a hormone released in response to food intake, particularly fat and protein. While CCK can contribute to satiety, it is not the primary hormone associated with this process.

**Clinical Pearl / High-Yield Fact**
Leptin levels are often elevated in obesity, and its dysregulation is thought to contribute to the development of metabolic disorders. Understanding the role of leptin in energy balance is crucial for developing effective treatments for obesity and related conditions.

**Correct Answer:** Leptin.