**Core Concept**
The treatment of Wilm's Tumor, a type of pediatric renal cancer, depends on the stage of the disease. **Stage-I Wilm's Tumor** is characterized by the tumor being limited to the kidney and completely resected.

**Why the Correct Answer is Right**
For **Stage-I Wilm's Tumor**, the treatment of choice involves a combination of **nephrectomy** (surgical removal of the kidney) and **adjuvant chemotherapy**, which has been shown to significantly improve outcomes.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it may not be specified.
**Option B:** Incorrect because it is not the standard treatment.
**Option C:** Incorrect as it is not typically the first line.
**Option D:** Incorrect because it is not the preferred choice.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that **surgery** is the primary treatment for Wilm's Tumor, and **chemotherapy** plays a crucial role in managing the disease, especially in preventing recurrence.

**Correct Answer:** D. Nephrectomy + Adjuvant Chemotherapy.