**Core Concept**
Metabolic syndrome is a cluster of conditions that increase the risk of developing type 2 diabetes and cardiovascular disease. It is characterized by a combination of insulin resistance, central obesity, dyslipidemia, and hypertension.

**Why the Correct Answer is Right**
High LDL (low-density lipoprotein) cholesterol is not a criterion for the diagnosis of metabolic syndrome. The American Heart Association and the National Heart, Lung, and Blood Institute (NHLBI) have established a set of criteria for diagnosing metabolic syndrome, which include central obesity, hypertension, hypertriglyceridemia, and low HDL (high-density lipoprotein) cholesterol. High LDL is not a specific criterion, but rather a general risk factor for cardiovascular disease. The focus of metabolic syndrome is on the clustering of specific risk factors, rather than individual lipid profiles.

**Why Each Wrong Option is Incorrect**
**Option A:** Hypertension is a criterion for the diagnosis of metabolic syndrome, as it is a key component of the condition.
**Option B:** Central obesity is a criterion for the diagnosis of metabolic syndrome, as it is a major risk factor for insulin resistance and metabolic dysfunction.
**Option C:** Hypertriglyceridemia is a criterion for the diagnosis of metabolic syndrome, as it is a marker of dyslipidemia and insulin resistance.

**Clinical Pearl / High-Yield Fact**
Remember that metabolic syndrome is not just about individual risk factors, but rather the clustering of multiple conditions that increase the risk of developing type 2 diabetes and cardiovascular disease.

**✓ Correct Answer: D. High LDL**