**Core Concept**
Nephrotic syndrome is a collection of symptoms resulting from severe damage to the glomeruli, the filtering units of the kidneys. It is characterized by massive proteinuria (excretion of large amounts of protein in the urine), hypoalbuminemia (low serum albumin), hyperlipidemia (elevated levels of lipids in the blood), and edema (swelling).

**Why the Correct Answer is Right**
The basic abnormality in nephrotic syndrome is the loss of the glomerular filtration barrier, which normally prevents the passage of large molecules like proteins and lipids into the urine. This loss of barrier function is due to the damage to the podocytes, specialized cells in the glomerulus that play a crucial role in maintaining the integrity of the filtration barrier. The podocytes are characterized by their foot processes, which interdigitate with each other and the adjacent glomerular basement membrane to form the filtration slits.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the basic abnormality in nephrotic syndrome.
**Option B:** While hyperlipidemia is a common feature of nephrotic syndrome, it is not the basic abnormality.
**Option C:** This option is not accurate, as the basic abnormality in nephrotic syndrome is not the absence of glomeruli.

**Clinical Pearl / High-Yield Fact**
The most common cause of nephrotic syndrome in children is minimal change disease, which is characterized by the loss of foot processes of the podocytes and is often responsive to corticosteroid therapy.

**Correct Answer:** C.