This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Kidney size is normal in 
Select and explain. 
A. Nephronophthisis, B. ADPCKD, C. Acquired renal cysts, D. Medullary sponge kidney
D: Medullary sponge kidney
Answer: D: Medullary sponge kidney 
Explanation: Kidney size :
Normal - Medullary sponge kidney, Simple renal cysts.
Small - Medullary Cystic kidney, Nephronophthisis .