## **Core Concept**
The question tests understanding of glucose transporters (GLUTs) and their regulation by insulin. Insulin-dependent glucose transporters facilitate glucose uptake in cells in response to insulin.

## **Why the Correct Answer is Right**
The correct answer, **GLUT4**, is primarily found in adipose tissue and striated muscle (skeletal and cardiac muscle). It is unique because its translocation to the cell surface is insulin-dependent. When insulin binds to its receptor on the cell surface, it triggers a signaling cascade that leads to the translocation of GLUT4 vesicles to the plasma membrane, increasing glucose uptake in these cells.

## **Why Each Wrong Option is Incorrect**
- **Option A: GLUT1** - This glucose transporter is widely distributed in various tissues and is responsible for basal glucose uptake. It is not primarily insulin-dependent.
- **Option B: GLUT2** - Primarily found in the liver, pancreas, and kidneys, GLUT2 plays a role in glucose sensing and glucose-stimulated insulin secretion but is not insulin-dependent for its glucose transport activity.
- **Option D: GLUT3** - This has a high affinity for glucose and is predominantly found in neurons and the placenta. Like GLUT1, it is not primarily regulated by insulin.

## **Clinical Pearl / High-Yield Fact**
A key clinical point to remember is that **insulin resistance**, a condition where the body's cells do not respond effectively to insulin, leads to decreased GLUT4 translocation and thus reduced glucose uptake in muscles and adipose tissue. This is a critical pathophysiological mechanism in type 2 diabetes mellitus.

## **Correct Answer: C. GLUT4**