**Core Concept**
During starvation, the body's metabolic state shifts from a reliance on glucose for energy to a reliance on fatty acids and ketone bodies. This transition involves the coordinated regulation of various enzymes involved in lipid and carbohydrate metabolism.

**Why the Correct Answer is Right**
The correct answer involves identifying the enzyme that is not involved in the catabolic pathways activated during starvation. In starvation, the activities of enzymes involved in lipolysis, such as hormone-sensitive lipase, are increased to mobilize fatty acids from adipose tissue. Additionally, enzymes involved in ketogenesis, such as HMG-CoA synthase, are also increased to produce ketone bodies from acetyl-CoA. However, the enzyme that is not increased in starvation is glucokinase, which is involved in glycolysis and glucose utilization.

**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because the activity of hormone-sensitive lipase is increased in starvation to mobilize fatty acids from adipose tissue.
* **Option B:** Incorrect because the activity of HMG-CoA synthase is increased in starvation to produce ketone bodies from acetyl-CoA.
* **Option C:** Incorrect because the activity of pyruvate dehydrogenase is increased in starvation to convert pyruvate to acetyl-CoA, which is then used for ketogenesis.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that during starvation, the body's metabolic state is characterized by a shift from glucose to ketone bodies as the primary energy source. This transition is mediated by the coordinated regulation of various enzymes involved in lipid and carbohydrate metabolism.

**Correct Answer:** D. Glucokinase.