This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney and ureter, Subject name: Surgery
Most common renal tumor in neonatal period: 
Select and explain. 
A. Renal cyst, B. Congenital mesoblastic nephroma, C. Neuroblastoma, D. Nephroblastoma
B: Congenital mesoblastic nephroma
Answer: B: Congenital mesoblastic nephroma 
Explanation: "Although congenital mesoblastic nephroma (CMN) is a rare benign congenital renal tumor it is the most common solid renal tumor in the neonatal period."