**Core Concept**
Nephrotic syndrome is characterized by a significant loss of protein, specifically albumin, through the urine, leading to hypoalbuminemia and edema. The syndrome is often associated with impaired renal function, particularly decreased glomerular filtration rate (GFR) and increased permeability of the glomerular capillaries.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of nephrotic syndrome, where the kidneys' ability to reabsorb proteins is compromised. In nephrotic syndrome, the glomerular basement membrane becomes more permeable, allowing larger molecules, including albumin, to pass through the filtration barrier. This leads to a decrease in serum albumin levels.

**Why Each Wrong Option is Incorrect**
**Option A:** Not provided
**Option B:** Not provided
**Option C:** Not provided
**Option D:** Not provided

**Clinical Pearl / High-Yield Fact**
In nephrotic syndrome, the loss of albumin in the urine can lead to a decrease in oncotic pressure, resulting in edema. Additionally, the increased permeability of the glomerular capillaries can also lead to the loss of other proteins, such as immunoglobulins, which can impair the immune system.

**Correct Answer:** D