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: Surgery
One of the following is characterised by RIM sign - 
Select and explain. 
A. Hydronephrosis (Gross), B. Hypernephroma, C. Chronic pyelonephritis, D. Polycystic kidney
A: Hydronephrosis (Gross)
Answer: A: Hydronephrosis (Gross) 
Explanation: None