Okay, let's tackle this question. The question is about where insulin-dependent glucose entry occurs. I need to remember which tissues require insulin for glucose uptake.

First, I recall that insulin facilitates glucose uptake in certain cells. The main ones are muscle and adipose tissue. These cells have glucose transporters called GLUT4, which translocate to the cell membrane in response to insulin. So, when insulin is present, GLUT4 moves to the membrane and allows glucose to enter the cell.

Other tissues like the liver don't rely on insulin for glucose uptake. The liver uses GLUT2 transporters, which don't require insulin. The same goes for the brain, which uses GLUT1 and GLUT3, which are insulin-independent. Red blood cells also use GLUT1, so they don't need insulin.

So the correct answer should be muscle and adipose tissue. The options might be listing these as correct. The other options, like liver or brain, would be incorrect because they don't depend on insulin for glucose entry. The question is testing the knowledge of insulin's role in glucose transport mechanisms across different tissues.

**Core Concept**
Insulin-dependent glucose uptake primarily occurs in skeletal muscle, adipose tissue, and cardiac muscle via GLUT4 transporters. These tissues require insulin to translocate GLUT4 from intracellular vesicles to the cell membrane, enabling glucose entry. Other tissues, like the liver and brain, use insulin-independent transporters.

**Why the Correct Answer is Right**
The correct answer likely includes **muscle** and **adipose tissue**. Insulin binds to its receptor on these cells, activating signaling pathways (e.g., PI3K/Akt) that trigger GLUT4 translocation to the plasma membrane. This process is critical for postprandial glucose disposal and maintaining glucose homeostasis. Without insulin, these cells cannot efficiently take up glucose, contributing to hyperglycemia in diabetes mellitus.

**Why Each Wrong Option is Incorrect**
**Option A:** *Liver* uses GLUT2, which is insulin-independent. The liver can take up and release glucose regardless of insulin levels.
**Option B:** *Brain* relies on GLUT1 and GLUT3, which are constitutively active and do not require insulin.
**Option D:** *Red blood cells* lack insulin receptors and use GLUT1 for glucose entry.

**Clinical Pearl / High-Yield Fact**
Remember the "3 Ms" for insulin-dependent glucose uptake: **Muscle**, **Myocardium (heart)**, and **Adipose tissue**. The liver and brain are classic examples of insulin-independent tissues. This distinction is crucial for understanding diabetes pathophysiology and treatment targets.

**Correct Answer: C. Skeletal muscle and adipose tissue**

✓ Correct Answer: C. Hea