**Core Concept**
Nephrotic syndrome is a clinical disorder characterized by severe proteinuria (>3.5 g/1.73 m^2/day), hypoalbuminemia, hyperlipidemia, and edema. It is primarily caused by damage to the glomerular filtration barrier in the kidneys, leading to the loss of large amounts of albumin and other proteins in the urine.

**Why the Correct Answer is Right**
The correct features of nephrotic syndrome include severe proteinuria, hypoalbuminemia, hyperlipidemia, and edema. Severe proteinuria occurs due to the loss of large amounts of albumin and other proteins in the urine, which is a hallmark of nephrotic syndrome. Hypoalbuminemia results from the loss of albumin in the urine, leading to decreased oncotic pressure and subsequent edema. Hyperlipidemia is also a characteristic feature of nephrotic syndrome, likely due to the increased production of lipids in response to the loss of albumin. Edema is a common symptom of nephrotic syndrome, resulting from the decreased oncotic pressure and increased permeability of the blood vessels.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because hematuria is not a feature of nephrotic syndrome. Hematuria is typically associated with nephritic syndrome, which is characterized by inflammation of the glomeruli.
**Option B:** This option is incorrect because hypertension is not a feature of nephrotic syndrome. While some patients with nephrotic syndrome may have hypertension, it is not a characteristic feature of the disorder.
**Option C:** This option is incorrect because oliguria is not a feature of nephrotic syndrome. Nephrotic syndrome is typically characterized by an increase in urine production, not a decrease.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that nephrotic syndrome is primarily caused by damage to the glomerular filtration barrier, leading to the loss of large amounts of albumin and other proteins in the urine. This can result in severe proteinuria, hypoalbuminemia, hyperlipidemia, and edema.

**Correct Answer: D. Oliguria**