**Core Concept**
Recurrent episodes of gross hematuria in a child suggest a congenital or acquired condition affecting the urinary tract, particularly the kidneys or bladder. This condition may involve structural abnormalities, inflammation, or tumors.

**Why the Correct Answer is Right**
The most likely diagnosis in this scenario is a **Wilm's tumor**, also known as a nephroblastoma. Wilm's tumor is a type of kidney cancer that primarily affects children, particularly those under the age of 6. It often presents with a triad of abdominal pain, hematuria, and a palpable abdominal mass. The tumor arises from the renal parenchyma and can invade surrounding structures, including the renal pelvis and calyces, leading to hematuria.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not specified, so we'll skip it.

**Option B:** While **Polycystic Kidney Disease (PKD)** can cause hematuria, it typically presents in older children and adults, and is characterized by the presence of multiple cysts in the kidneys. PKD is a genetic disorder that affects the kidneys' ability to filter waste and excess fluids, leading to kidney enlargement and potential complications.

**Option C:** **Glomerulonephritis** can cause hematuria, but it is typically associated with a more systemic presentation, including hypertension, proteinuria, and renal insufficiency. Glomerulonephritis is an inflammatory condition affecting the glomeruli, the filtering units of the kidneys.

**Clinical Pearl / High-Yield Fact**
Wilm's tumor is the most common type of kidney cancer in children, accounting for about 9 in 10 cases. Early detection and treatment can significantly improve outcomes, highlighting the importance of prompt evaluation and diagnosis in children presenting with hematuria.

**Correct Answer: C. Glomerulonephritis**