## Core Concept
Syndrome X, also known as metabolic syndrome, is a cluster of conditions that occur together, increasing the risk of heart disease, stroke, and type 2 diabetes. These conditions include central obesity, high blood pressure, elevated fasting plasma glucose, high serum triglycerides, and low high-density lipoprotein (HDL) levels.

## Why the Correct Answer is Right
The correct answer, , is associated with a characteristic that does not align with the typical features or management strategies of syndrome X. Insulin resistance is a key feature of metabolic syndrome, and treatments often focus on improving insulin sensitivity and managing the individual components of the syndrome.

## Why Each Wrong Option is Incorrect
* **Option A:** This option is incorrect because central obesity is indeed a characteristic of syndrome X. It is one of the diagnostic criteria.
* **Option B:** This option is incorrect as well; insulin resistance is a core pathophysiological feature of syndrome X.
* **Option C:** Similarly, this option is incorrect because hypertension is another common feature of syndrome X.

## Clinical Pearl / High-Yield Fact
A key clinical pearl for syndrome X (metabolic syndrome) is that the presence of three or more of the following criteria is required for diagnosis: waist circumference ≥102 cm in men or ≥88 cm in women, blood pressure ≥130/≥85 mmHg, fasting glucose ≥110 mg/dL (or on treatment for hyperglycemia), serum triglycerides ≥150 mg/dL, and HDL cholesterol <40 mg/dL in men or <50 mg/dL in women. ## Correct Answer: D.