This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Childhood tumors, Subject name: Pediatrics
Which of the following is the treatment of choice for stage-I Wilm's Tumor 
Select and explain. 
A. Laparoscopic Nephrectomy, B. Open Nephroureterectomy, C. Chemotherapy, D. Observation
B: Open Nephroureterectomy
Answer: B: Open Nephroureterectomy 
Explanation: Open Nephroureterectomy is the standard surgical procedure for Wilms tumour.Many expes prefer preoperative chemotherapy because it diminishes the size of the tumor and allows better staging.By preoperative chemotherapy,using actinomycin D and vincristine for a period of 4 weeks,85% of the patients may not require any local radiotherapy.Stage I and II tumors with orable histology are usually treated postoperatively with vincristine & actinomycin D. Reference:Essential pediatrics-Ghai,8th edition,page no:618.