**Core Concept**
Insulin plays a crucial role in glucose metabolism and lipid synthesis, promoting lipogenesis by activating key enzymes and pathways in the liver and adipose tissue. Insulin stimulates the de novo synthesis of fatty acids from glucose through the action of acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS).

**Why the Correct Answer is Right**
Insulin binds to its receptor, triggering a series of intracellular signaling cascades that ultimately lead to the activation of phosphatidylinositol 3-kinase (PI3K) and protein kinase B (Akt). Activated Akt phosphorylates and activates ACC, which in turn increases the synthesis of malonyl-CoA, a key intermediate in fatty acid synthesis. Additionally, insulin promotes the translocation of glucose transporter type 4 (GLUT4) to the plasma membrane, facilitating glucose uptake in adipocytes and promoting lipogenesis.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because insulin does indeed promote lipogenesis by stimulating the activity of fatty acid synthase (FAS), which is a key enzyme in the synthesis of fatty acids from glucose.
* **Option B:** This option is incorrect because insulin stimulates the activity of acetyl-CoA carboxylase (ACC), which is a key regulatory enzyme in the synthesis of fatty acids from glucose. ACC is activated by insulin, leading to increased lipogenesis.
* **Option C:** This option is incorrect because insulin promotes lipogenesis by stimulating the activity of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC), as well as by promoting glucose uptake in adipocytes through the translocation of GLUT4.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that insulin resistance, a hallmark of type 2 diabetes, is characterized by impaired glucose uptake in adipocytes and reduced lipogenesis. This can lead to increased lipolysis and the release of free fatty acids into the bloodstream, contributing to the development of insulin resistance and other metabolic complications.

**Correct Answer: D.**