**Core Concept**
The glomerular basement membrane (GBM) is a selective barrier that filters blood components based on molecular size, charge, and shape. Charge-dependent filtration is a critical process that allows negatively charged molecules to be retained in the blood, while positively charged molecules can pass through.

**Why the Correct Answer is Right**
The protein responsible for charge-dependent filtration in the glomerular basement membrane is negatively charged heparan sulfate proteoglycan. This proteoglycan is embedded in the GBM and has a high density of negatively charged sulfate groups. As a result, negatively charged molecules in the blood, such as albumin, are electrostatically repelled by the heparan sulfate proteoglycan and are retained in the blood. This selective barrier ensures that only small, uncharged molecules, such as water and glucose, can pass through the GBM and into the urine.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not specify a protein or molecule with known charge-dependent filtration properties.
* **Option B:** This option is incorrect as it refers to a different type of protein that is not primarily involved in charge-dependent filtration.
* **Option C:** This option is incorrect as it is not a protein or molecule known to be involved in charge-dependent filtration in the glomerular basement membrane.

**Clinical Pearl / High-Yield Fact**
The glomerular basement membrane is a dynamic structure that can be altered by various disease states, including diabetes mellitus and hypertension. Damage to the GBM can lead to changes in charge-dependent filtration, resulting in proteinuria or albuminuria.

**Correct Answer:**
Nidogen (also known as entactin) **Correct Answer:**
Nidogen (also known as entactin)